diff --git a/mirai-api-http/src/main/kotlin/net/mamoe/mirai/api/http/data/common/MessageDTO.kt b/mirai-api-http/src/main/kotlin/net/mamoe/mirai/api/http/data/common/MessageDTO.kt
index 187c49a0e..8e00bc629 100644
--- a/mirai-api-http/src/main/kotlin/net/mamoe/mirai/api/http/data/common/MessageDTO.kt
+++ b/mirai-api-http/src/main/kotlin/net/mamoe/mirai/api/http/data/common/MessageDTO.kt
@@ -103,6 +103,7 @@ suspend fun MessagePacket<*, *>.toDTO() = when (this) {
 suspend fun MessageChainDTO.toMessageChain(contact: Contact) =
     buildMessageChain { this@toMessageChain.forEach { it.toMessage(contact)?.let(::add) } }
 
+
 @UseExperimental(ExperimentalUnsignedTypes::class)
 suspend fun MessagePacket<*, *>.messageDTO(message: Message) = when (message) {
     is MessageSource -> MessageSourceDTO(message.id)
diff --git a/mirai-console/src/main/kotlin/net/mamoe/mirai/console/plugins/ConfigSection.kt b/mirai-console/src/main/kotlin/net/mamoe/mirai/console/plugins/ConfigSection.kt
index 453c5adb2..e80676438 100644
--- a/mirai-console/src/main/kotlin/net/mamoe/mirai/console/plugins/ConfigSection.kt
+++ b/mirai-console/src/main/kotlin/net/mamoe/mirai/console/plugins/ConfigSection.kt
@@ -17,8 +17,11 @@ import com.moandjiezana.toml.Toml
 import com.moandjiezana.toml.TomlWriter
 import kotlinx.serialization.Serializable
 import kotlinx.serialization.UnstableDefault
+import net.mamoe.mirai.utils.io.encodeToString
 import org.yaml.snakeyaml.Yaml
+import tornadofx.c
 import java.io.File
+import java.io.InputStream
 import java.util.*
 import java.util.concurrent.ConcurrentHashMap
 import kotlin.collections.LinkedHashMap
@@ -69,6 +72,9 @@ interface Config {
             )
         }
 
+        /**
+         * create a read-write config
+         * */
         fun load(file: File): Config {
             if (!file.exists()) {
                 file.createNewFile()
@@ -86,6 +92,32 @@ interface Config {
                 else -> error("Unsupported file config type ${file.extension.toLowerCase()}")
             }
         }
+
+        /**
+         * create a read-only config
+         */
+        fun load(content: String, type: String): Config {
+            return when (type.toLowerCase()) {
+                "json" -> JsonConfig(content)
+                "yml" -> YamlConfig(content)
+                "yaml" -> YamlConfig(content)
+                "mirai" -> YamlConfig(content)
+                "ini" -> TomlConfig(content)
+                "toml" -> TomlConfig(content)
+                "properties" -> TomlConfig(content)
+                "property" -> TomlConfig(content)
+                "data" -> TomlConfig(content)
+                else -> error("Unsupported file config type $content")
+            }
+        }
+
+        /**
+         * create a read-only config
+         */
+        fun load(inputStream: InputStream, type: String): Config {
+            return load(inputStream.readBytes().encodeToString(), type)
+        }
+
     }
 }
 
@@ -363,14 +395,23 @@ interface FileConfig : Config {
 
 
 abstract class FileConfigImpl internal constructor(
-    private val file: File
+    private val rawContent: String
 ) : FileConfig,
     ConfigSection {
 
-    private val content by lazy {
-        deserialize(file.readText())
+    internal var file: File? = null
+
+
+    constructor(file: File) : this(file.readText()) {
+        this.file = file
     }
 
+
+    private val content by lazy {
+        deserialize(rawContent)
+    }
+
+
     override val size: Int get() = content.size
     override val entries: MutableSet<MutableMap.MutableEntry<String, Any>> get() = content.entries
     override val keys: MutableSet<String> get() = content.keys
@@ -384,12 +425,17 @@ abstract class FileConfigImpl internal constructor(
     override fun remove(key: String): Any? = content.remove(key)
 
     override fun save() {
-        if (!file.exists()) {
-            file.createNewFile()
+        if (isReadOnly()) {
+            error("Config is readonly")
         }
-        file.writeText(serialize(content))
+        if (!((file?.exists())!!)) {
+            file?.createNewFile()
+        }
+        file?.writeText(serialize(content))
     }
 
+    fun isReadOnly() = file == null
+
     override fun contains(key: String): Boolean {
         return content.contains(key)
     }
@@ -409,8 +455,12 @@ abstract class FileConfigImpl internal constructor(
 }
 
 class JsonConfig internal constructor(
-    file: File
-) : FileConfigImpl(file) {
+    content: String
+) : FileConfigImpl(content) {
+    constructor(file: File) : this(file.readText()) {
+        this.file = file
+    }
+
     @UnstableDefault
     override fun deserialize(content: String): ConfigSection {
         if (content.isEmpty() || content.isBlank() || content == "{}") {
@@ -429,7 +479,11 @@ class JsonConfig internal constructor(
     }
 }
 
-class YamlConfig internal constructor(file: File) : FileConfigImpl(file) {
+class YamlConfig internal constructor(content: String) : FileConfigImpl(content) {
+    constructor(file: File) : this(file.readText()) {
+        this.file = file
+    }
+
     override fun deserialize(content: String): ConfigSection {
         if (content.isEmpty() || content.isBlank()) {
             return ConfigSectionImpl()
@@ -447,7 +501,11 @@ class YamlConfig internal constructor(file: File) : FileConfigImpl(file) {
 
 }
 
-class TomlConfig internal constructor(file: File) : FileConfigImpl(file) {
+class TomlConfig internal constructor(content: String) : FileConfigImpl(content) {
+    constructor(file: File) : this(file.readText()) {
+        this.file = file
+    }
+
     override fun deserialize(content: String): ConfigSection {
         if (content.isEmpty() || content.isBlank()) {
             return ConfigSectionImpl()
diff --git a/mirai-console/src/main/kotlin/net/mamoe/mirai/console/plugins/PluginBase.kt b/mirai-console/src/main/kotlin/net/mamoe/mirai/console/plugins/PluginBase.kt
index dd526deee..4d1bd6f07 100644
--- a/mirai-console/src/main/kotlin/net/mamoe/mirai/console/plugins/PluginBase.kt
+++ b/mirai-console/src/main/kotlin/net/mamoe/mirai/console/plugins/PluginBase.kt
@@ -17,6 +17,7 @@ import net.mamoe.mirai.utils.MiraiLogger
 import net.mamoe.mirai.utils.SimpleLogger
 import net.mamoe.mirai.utils.io.encodeToString
 import java.io.File
+import java.io.InputStream
 import java.net.URL
 import java.net.URLClassLoader
 import java.util.jar.JarFile
@@ -91,6 +92,13 @@ abstract class PluginBase(coroutineContext: CoroutineContext) : CoroutineScope {
     val logger: MiraiLogger by lazy {
         DefaultLogger(pluginDescription.name)
     }
+
+    fun getResources(fileName: String): InputStream? {
+        return PluginManager.getFileInJarByName(
+            this.pluginDescription.name,
+            fileName
+        )
+    }
 }
 
 class PluginDescription(
@@ -325,6 +333,47 @@ object PluginManager {
             it.disable(throwable)
         }
     }
+
+    /**
+     * 根据插件名字找Jar的文件
+     * null => 没找到
+     */
+    fun getJarPath(pluginName: String): File? {
+        File(pluginsPath).listFiles()?.forEach { file ->
+            if (file != null && file.extension == "jar") {
+                val jar = JarFile(file)
+                val pluginYml =
+                    jar.entries().asSequence().filter { it.name.toLowerCase().contains("plugin.yml") }.firstOrNull()
+                if (pluginYml != null) {
+                    val description =
+                        PluginDescription.readFromContent(
+                            URL("jar:file:" + file.absoluteFile + "!/" + pluginYml.name).openConnection().inputStream.use {
+                                it.readBytes().encodeToString()
+                            })
+                    if (description.name.toLowerCase() == pluginName.toLowerCase()) {
+                        return file
+                    }
+                }
+            }
+        }
+        return null
+    }
+
+
+    /**
+     * 根据插件名字找Jar resources中的文件
+     * null => 没找到
+     */
+    fun getFileInJarByName(pluginName: String, toFind: String): InputStream? {
+        val jarFile = getJarPath(pluginName)
+        if (jarFile == null) {
+            return null
+        }
+        val jar = JarFile(jarFile)
+        val toFindFile =
+            jar.entries().asSequence().filter { it.name == toFind }.firstOrNull() ?: return null
+        return URL("jar:file:" + jarFile.absoluteFile + "!/" + toFindFile.name).openConnection().inputStream
+    }
 }
 
 
diff --git a/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/message/messages.kt b/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/message/messages.kt
index 86261c518..875502082 100644
--- a/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/message/messages.kt
+++ b/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/message/messages.kt
@@ -326,7 +326,7 @@ internal class NotOnlineImageFromServer(
 internal fun MsgComm.Msg.toMessageChain(): MessageChain {
     val elements = this.msgBody.richText.elems
 
-    val message = ArrayList<Message>(elements.size + 1)
+    val message = MessageChainBuilder(elements.size + 1)
     message.add(MessageSourceFromMsg(delegate = this))
     elements.joinToMessageChain(message)
     return message.asMessageChain()
@@ -338,7 +338,7 @@ internal fun MsgComm.Msg.toMessageChain(): MessageChain {
 internal fun ImMsgBody.SourceMsg.toMessageChain(): MessageChain {
     val elements = this.elems!!
 
-    val message = ArrayList<Message>(elements.size + 1)
+    val message = MessageChainBuilder(elements.size + 1)
     message.add(MessageSourceFromServer(delegate = this))
     elements.joinToMessageChain(message)
     return message.asMessageChain()
@@ -346,7 +346,7 @@ internal fun ImMsgBody.SourceMsg.toMessageChain(): MessageChain {
 
 
 @UseExperimental(MiraiInternalAPI::class, ExperimentalUnsignedTypes::class, MiraiDebugAPI::class)
-internal fun List<ImMsgBody.Elem>.joinToMessageChain(message: MutableList<Message>) {
+internal fun List<ImMsgBody.Elem>.joinToMessageChain(message: MessageChainBuilder) {
     this.forEach {
         when {
             it.srcMsg != null -> message.add(QuoteReply(MessageSourceFromServer(it.srcMsg)))
diff --git a/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/network/protocol/packet/chat/receive/MessageSvc.kt b/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/network/protocol/packet/chat/receive/MessageSvc.kt
index b2dab4e51..7207413db 100644
--- a/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/network/protocol/packet/chat/receive/MessageSvc.kt
+++ b/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/network/protocol/packet/chat/receive/MessageSvc.kt
@@ -285,7 +285,7 @@ internal class MessageSvc {
 
             @UseExperimental(MiraiExperimentalAPI::class)
             fun startWaitingSequenceId(contact: Contact) {
-                sequenceIdDeferred = contact.subscribingGetAsync<OnlinePush.PbPushGroupMsg.SendGroupMessageReceipt, Int> {
+                sequenceIdDeferred = contact.subscribingGetAsync<OnlinePush.PbPushGroupMsg.SendGroupMessageReceipt, Int>(timeoutMillis = 3000) {
                     if (it.messageRandom == this@MessageSourceFromSend.messageRandom) {
                         it.sequenceId
                     } else null
diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/Contact.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/Contact.kt
index 07cf36239..678af1d00 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/Contact.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/Contact.kt
@@ -138,9 +138,5 @@ suspend inline fun <C : Contact> C.sendMessage(message: Message): MessageReceipt
 /**
  * @see Contact.sendMessage
  */
-suspend inline fun <C : Contact> C.sendMessage(plain: String): MessageReceipt<C> = sendMessage(plain.toMessage())
-
-/**
- * @see Contact.sendMessage
- */
-suspend inline fun <C : Contact> C.sendMessage(plain: CombinedMessage): MessageReceipt<C> = sendMessage(MessageChain(plain as Message)) as MessageReceipt<C>
\ No newline at end of file
+@Suppress("UNCHECKED_CAST")
+suspend inline fun <C : Contact> C.sendMessage(plain: String): MessageReceipt<C> = sendMessage(plain.toMessage())
\ No newline at end of file
diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/At.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/At.kt
index e21f476ea..f2413eea3 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/At.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/At.kt
@@ -26,7 +26,8 @@ import kotlin.jvm.JvmName
  *
  * @see AtAll 全体成员
  */
-class At @MiraiInternalAPI constructor(val target: Long, val display: String) : Message {
+class At
+@MiraiInternalAPI constructor(val target: Long, val display: String) : Message, MessageContent {
     @UseExperimental(MiraiInternalAPI::class)
     constructor(member: Member) : this(member.id, "@${member.nameCardOrNick}")
 
@@ -38,9 +39,9 @@ class At @MiraiInternalAPI constructor(val target: Long, val display: String) :
 
     override fun followedBy(tail: Message): CombinedMessage {
         if (tail is PlainText && tail.stringValue.startsWith(' ')) {
-            return super.followedBy(tail)
+            return super<MessageContent>.followedBy(tail)
         }
-        return super.followedBy(PlainText(" ")) + tail
+        return super<MessageContent>.followedBy(PlainText(" ")) + tail
     }
 }
 
diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/AtAll.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/AtAll.kt
index 0b9369bdd..df748ddd5 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/AtAll.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/AtAll.kt
@@ -22,15 +22,15 @@ import kotlin.jvm.JvmName
  *
  * @see At at 单个群成员
  */
-object AtAll : Message, Message.Key<AtAll> {
+object AtAll : Message, Message.Key<AtAll>, MessageContent {
     override fun toString(): String = "@全体成员"
 
     // 自动为消息补充 " "
 
     override fun followedBy(tail: Message): CombinedMessage {
         if (tail is PlainText && tail.stringValue.startsWith(' ')) {
-            return super.followedBy(tail)
+            return super<MessageContent>.followedBy(tail)
         }
-        return super.followedBy(PlainText(" ")) + tail
+        return super<MessageContent>.followedBy(PlainText(" ")) + tail
     }
 }
\ No newline at end of file
diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/CombinedMessage.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/CombinedMessage.kt
index 081c1116b..c29b85149 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/CombinedMessage.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/CombinedMessage.kt
@@ -7,8 +7,14 @@
  * https://github.com/mamoe/mirai/blob/master/LICENSE
  */
 
+@file:JvmMultifileClass
+@file:JvmName("MessageUtils")
+
 package net.mamoe.mirai.message.data
 
+import kotlin.jvm.JvmMultifileClass
+import kotlin.jvm.JvmName
+
 /**
  * Left-biased list
  */
@@ -16,6 +22,8 @@ class CombinedMessage(
     val left: Message,
     val element: Message
 ) : Iterable<Message>, Message {
+
+    // 不要把它用作 local function, 会编译错误
     private suspend fun SequenceScope<Message>.yieldCombinedOrElements(message: Message) {
         when (message) {
             is CombinedMessage -> {
@@ -36,6 +44,6 @@ class CombinedMessage(
     }
 
     override fun toString(): String {
-        return left.toString() + element.toString()
+        return element.toString() + left.toString()
     }
 }
\ No newline at end of file
diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/Face.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/Face.kt
index 0578b7c9d..88da0932c 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/Face.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/Face.kt
@@ -18,7 +18,7 @@ import kotlin.jvm.JvmName
 /**
  * QQ 自带表情
  */
-class Face(val id: Int) : Message {
+class Face(val id: Int) : Message, MessageContent {
     override fun toString(): String = "[mirai:face$id]"
 
     /**
diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/Image.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/Image.kt
index d11c80488..f86ff59b4 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/Image.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/Image.kt
@@ -25,7 +25,7 @@ import kotlin.jvm.JvmStatic
 /**
  * 自定义表情 (收藏的表情), 图片
  */
-sealed class Image : Message {
+sealed class Image : Message, MessageContent {
     companion object Key : Message.Key<Image> {
         @JvmStatic
         @JsName("fromId")
diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/Message.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/Message.kt
index aba05812d..95e068f0a 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/Message.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/Message.kt
@@ -20,6 +20,12 @@ import kotlin.jvm.JvmSynthetic
  * 可发送的或从服务器接收的消息.
  * 采用这样的消息模式是因为 QQ 的消息多元化, 一条消息中可包含 [纯文本][PlainText], [图片][Image] 等.
  *
+ * [消息][Message] 分为
+ * - [MessageMetadata] 消息元数据, 包括: [消息来源][MessageSource]
+ * - [MessageContent] 单个消息, 包括: [纯文本][PlainText], [@群员][At], [@全体成员][AtAll] 等.
+ * - [CombinedMessage] 通过 [plus] 连接的两个消息. 可通过 [asMessageChain] 转换为 [MessageChain]
+ * - [MessageChain] 不可变消息链, 即 [List] 形式链接的多个 [Message] 实例.
+ *
  * **在 Kotlin 使用 [Message]**
  * 这与使用 [String] 的使用非常类似.
  *
@@ -44,7 +50,12 @@ import kotlin.jvm.JvmSynthetic
  * @see PlainText 纯文本
  * @see Image 图片
  * @see Face 表情
+ * @see At 引用一个群成员
+ * @see AtAll 引用全体成员
+ * @see QuoteReply 引用一条消息
+ *
  * @see MessageChain 消息链(即 `List<Message>`)
+ * @see buildMessageChain 构造一个 [MessageChain]
  *
  * @see Contact.sendMessage 发送消息
  */
@@ -86,8 +97,6 @@ interface Message {
      */
     @JvmSynthetic // in java they should use `plus` instead
     fun followedBy(tail: Message): CombinedMessage {
-        require(tail !is SingleOnly) { "SingleOnly Message cannot follow another message" }
-        require(this !is SingleOnly) { "SingleOnly Message cannot be followed" }
         return CombinedMessage(tail, this)
     }
 
@@ -100,12 +109,37 @@ interface Message {
     operator fun plus(another: CharSequence): CombinedMessage = this.followedBy(another.toString().toMessage())
 }
 
+suspend fun <C : Contact> Message.sendTo(contact: C): MessageReceipt<C> {
+    return contact.sendMessage(this)
+}
+
+interface SingleMessage : Message
+
 /**
- * 表示这个 [Message] 仅能单个存在, 无法被连接.
+ * 消息元数据, 即不含内容的元素.
+ * 包括: [MessageSource]
  */
-interface SingleOnly : Message
+interface MessageMetadata : SingleMessage {
+    /*
+    fun iterator(): Iterator<Message> {
+        return object : Iterator<Message> {
+            var visited: Boolean = false
+            override fun hasNext(): Boolean = !visited
+            override fun next(): Message {
+                if (visited) throw NoSuchElementException()
+                return this@MessageMetadata.also { visited = true }
+            }
+        }
+    }*/
+}
+
+/**
+ * 消息内容
+ */
+interface MessageContent : SingleMessage
 
 /**
  * 将 [this] 发送给指定联系人
  */
-suspend inline fun <C : Contact> Message.sendTo(contact: C): MessageReceipt<C> = contact.sendMessage(this)
\ No newline at end of file
+@Suppress("UNCHECKED_CAST")
+suspend inline fun <C : Contact> MessageChain.sendTo(contact: C): MessageReceipt<C> = contact.sendMessage(this) as MessageReceipt<C>
\ No newline at end of file
diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/MessageChain.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/MessageChain.kt
index 529121372..54022e572 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/MessageChain.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/MessageChain.kt
@@ -16,27 +16,19 @@ import net.mamoe.mirai.message.data.NullMessageChain.toString
 import kotlin.js.JsName
 import kotlin.jvm.JvmMultifileClass
 import kotlin.jvm.JvmName
+import kotlin.jvm.JvmSynthetic
 import kotlin.reflect.KProperty
 
 /**
- * 消息链. 即 MutableList<Message>.
+ * 消息链.
  * 它的一般实现为 [MessageChainImpl], `null` 实现为 [NullMessageChain]
  *
- * 有关 [MessageChain] 的创建和连接:
- * - 当任意两个不是 [MessageChain] 的 [Message] 相连接后, 将会产生一个 [MessageChain].
- * - 若两个 [MessageChain] 连接, 后一个将会被合并到第一个内.
- * - 若一个 [MessageChain] 与一个其他 [Message] 连接, [Message] 将会被添加入 [MessageChain].
- * - 若一个 [Message] 与一个 [MessageChain] 连接, [Message] 将会被添加入 [MessageChain].
- *
  * 要获取更多信息, 请查看 [Message]
  *
- * @see buildMessageChain
+ * @see buildMessageChain 构造一个 [MessageChain]
  */
-interface MessageChain : Message, List<Message> {
-    // region Message override
+interface MessageChain : Message, Iterable<SingleMessage> {
     override operator fun contains(sub: String): Boolean
-    // endregion
-
     override fun toString(): String
 
     /**
@@ -51,29 +43,16 @@ interface MessageChain : Message, List<Message> {
  * 遍历每一个有内容的消息, 即 [At], [AtAll], [PlainText], [Image], [Face], [XMLMessage]
  */
 inline fun MessageChain.foreachContent(block: (Message) -> Unit) {
-    this.forEachIndexed { index: Int, message: Message ->
+    var last: Message? = null
+    this.forEach { message: Message ->
         if (message is At) {
-            if (index == 0 || this[index - 1] !is QuoteReply) {
+            if (last != null || last !is QuoteReply) {
                 block(message)
             }
-        } else if (message.hasContent()) {
+        } else if (message is MessageContent) {
             block(message)
         }
-    }
-}
-
-/**
- * 判断这个 [Message] 是否含有内容, 即是否为 [At], [AtAll], [PlainText], [Image], [Face], [XMLMessage]
- */
-fun Message.hasContent(): Boolean {
-    return when (this) {
-        is At,
-        is AtAll,
-        is PlainText,
-        is Image,
-        is Face,
-        is XMLMessage -> true
-        else -> false
+        last = message
     }
 }
 
@@ -99,7 +78,7 @@ fun MessageChain(): MessageChain = EmptyMessageChain
 @Suppress("FunctionName")
 fun MessageChain(vararg messages: Message): MessageChain =
     if (messages.isEmpty()) EmptyMessageChain
-    else MessageChainImpl(messages.toMutableList())
+    else MessageChainImpl(messages.asSequence().flatten())
 
 /**
  * 构造 [MessageChain] 的快速途径 (无 [Array] 创建)
@@ -109,7 +88,10 @@ fun MessageChain(vararg messages: Message): MessageChain =
 @JsName("newChain")
 @Suppress("FunctionName")
 fun MessageChain(message: Message): MessageChain =
-    MessageChainImpl(listOf(message))
+    when (message) {
+        is SingleMessage -> SingleMessageChainImpl(message)
+        else -> MessageChainImpl(message.flatten().asIterable())
+    }
 
 /**
  * 构造 [MessageChain]
@@ -118,7 +100,7 @@ fun MessageChain(message: Message): MessageChain =
 @JsName("newChain")
 @Suppress("FunctionName")
 fun MessageChain(messages: Iterable<Message>): MessageChain =
-    MessageChainImpl(messages.toList())
+    MessageChainImpl(messages.flatten().asIterable())
 
 /**
  * 构造 [MessageChain]
@@ -127,7 +109,7 @@ fun MessageChain(messages: Iterable<Message>): MessageChain =
 @JsName("newChain")
 @Suppress("FunctionName")
 fun MessageChain(messages: List<Message>): MessageChain =
-    MessageChainImpl(messages)
+    MessageChainImpl(messages.flatten().asIterable())
 
 
 /**
@@ -135,14 +117,34 @@ fun MessageChain(messages: List<Message>): MessageChain =
  * 若 [this] 为 [MessageChain] 将直接返回 this
  * 否则将调用 [MessageChain] 构造一个 [MessageChainImpl]
  */
-@Suppress("NOTHING_TO_INLINE")
-inline fun Message.toChain(): MessageChain = if (this is MessageChain) this else MessageChain(this)
+@Suppress("NOTHING_TO_INLINE", "UNCHECKED_CAST")
+@JvmSynthetic
+fun Message.toChain(): MessageChain = when (this) {
+    is MessageChain -> this
+    is CombinedMessage -> MessageChainImpl((this as Iterable<Message>).flatten().asIterable())
+    else -> SingleMessageChainImpl(this as SingleMessage)
+}
 
-/**
- * 构造 [MessageChain]
- */
+@JvmName("asMessageChain1")
+@JvmSynthetic
 @Suppress("unused", "NOTHING_TO_INLINE")
-inline fun List<Message>.asMessageChain(): MessageChain = MessageChain(this)
+fun Iterable<SingleMessage>.asMessageChain(): MessageChain = MessageChainImpl(this)
+
+@JvmSynthetic
+@Suppress("unused", "NOTHING_TO_INLINE")
+fun Iterable<Message>.asMessageChain(): MessageChain = MessageChainImpl(this.flatten())
+
+fun Iterable<Message>.flatten(): Sequence<SingleMessage> = asSequence().flatten()
+
+fun Sequence<Message>.flatten(): Sequence<SingleMessage> = flatMap { it.flatten() }
+
+fun Message.flatten(): Sequence<SingleMessage> {
+    return when (this) {
+        is MessageChain -> this.asSequence()
+        is CombinedMessage -> this.asSequence().flatten()
+        else -> sequenceOf(this as SingleMessage)
+    }
+}
 
 /**
  * 获取第一个 [M] 类型的 [Message] 实例
@@ -189,9 +191,7 @@ fun <M : Message> MessageChain.first(key: Message.Key<M>): M = firstOrNull(key)
 @Suppress("UNCHECKED_CAST")
 fun <M : Message> MessageChain.any(key: Message.Key<M>): Boolean = firstOrNull(key) != null
 
-object EmptyMessageChain : MessageChain by {
-    MessageChainImpl(emptyList())
-}()
+object EmptyMessageChain : MessageChain by MessageChainImpl(emptyList())
 
 /**
  * Null 的 [MessageChain].
@@ -200,45 +200,27 @@ object EmptyMessageChain : MessageChain by {
  * 除 [toString] 外, 其他方法均 [error]
  */
 object NullMessageChain : MessageChain {
-    override fun subList(fromIndex: Int, toIndex: Int): MutableList<Message> = error("accessing NullMessageChain")
-
     override fun toString(): String = "null"
-
     override fun contains(sub: String): Boolean = error("accessing NullMessageChain")
-    override fun contains(element: Message): Boolean = error("accessing NullMessageChain")
     override fun followedBy(tail: Message): CombinedMessage = CombinedMessage(left = EmptyMessageChain, element = tail)
-
-    override val size: Int get() = error("accessing NullMessageChain")
-    override fun containsAll(elements: Collection<Message>): Boolean = error("accessing NullMessageChain")
-    override fun get(index: Int): Message = error("accessing NullMessageChain")
-    override fun indexOf(element: Message): Int = error("accessing NullMessageChain")
-    override fun isEmpty(): Boolean = error("accessing NullMessageChain")
-    override fun iterator(): MutableIterator<Message> = error("accessing NullMessageChain")
-
-    override fun lastIndexOf(element: Message): Int = error("accessing NullMessageChain")
-    override fun listIterator(): MutableListIterator<Message> = error("accessing NullMessageChain")
-
-    override fun listIterator(index: Int): MutableListIterator<Message> = error("accessing NullMessageChain")
+    override fun iterator(): MutableIterator<SingleMessage> = error("accessing NullMessageChain")
 }
 
-/**
- * [MessageChain] 实现
- * 它是一个特殊的 [Message], 实现 [MutableList] 接口, 但将所有的接口调用都转到内部维护的另一个 [MutableList].
- */
+@PublishedApi
 internal class MessageChainImpl constructor(
-    /**
-     * Elements will not be instances of [MessageChain]
-     */
-    private val delegate: List<Message>
-) : Message, List<Message> by delegate, MessageChain {
-    override fun toString(): String = this.delegate.joinToString("") { it.toString() }
+    private val delegate: Iterable<SingleMessage>
+) : Message, Iterable<SingleMessage> by delegate, MessageChain {
+    constructor(delegate: Sequence<SingleMessage>) : this(delegate.asIterable())
 
+    override fun toString(): String = this.delegate.joinToString("") { it.toString() }
     override operator fun contains(sub: String): Boolean = delegate.any { it.contains(sub) }
-    override fun followedBy(tail: Message): CombinedMessage {
-        require(tail !is SingleOnly) { "SingleOnly Message cannot follow another message" }
-        // if (tail is MessageChain) tail.forEach { child -> this.followedBy(child) }
-        // else this.delegate.add(tail)
-        return CombinedMessage(tail, this)
-    }
 }
 
+@PublishedApi
+internal class SingleMessageChainImpl constructor(
+    private val delegate: SingleMessage
+) : Message, Iterable<SingleMessage> by listOf(delegate), MessageChain {
+    override fun toString(): String = this.delegate.toString()
+
+    override operator fun contains(sub: String): Boolean = sub in delegate
+}
\ No newline at end of file
diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/MessageSource.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/MessageSource.kt
index e57f8711c..992129835 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/MessageSource.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/MessageSource.kt
@@ -23,7 +23,7 @@ import kotlin.jvm.JvmName
  *
  * @see MessageSource.quote 引用这条消息, 创建 [MessageChain]
  */
-interface MessageSource : Message {
+interface MessageSource : Message, MessageMetadata {
     companion object Key : Message.Key<MessageSource>
 
     /**
diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/PlainText.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/PlainText.kt
index 36fc92c02..e76a34e2b 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/PlainText.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/PlainText.kt
@@ -21,7 +21,7 @@ import kotlin.jvm.JvmStatic
  *
  * 一般不需要主动构造 [PlainText], [Message] 可直接与 [String] 相加. Java 用户请使用 [MessageChain.plus]
  */
-inline class PlainText(val stringValue: String) : Message {
+inline class PlainText(val stringValue: String) : Message, MessageContent {
     constructor(charSequence: CharSequence) : this(charSequence.toString())
 
     override operator fun contains(sub: String): Boolean = sub in stringValue
diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/QuoteReply.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/QuoteReply.kt
index 494a1f280..137389190 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/QuoteReply.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/QuoteReply.kt
@@ -21,25 +21,27 @@ import kotlin.jvm.JvmName
 
 
 /**
- * 群内的或好友的引用回复.
+ * 从服务器接收的或客户端构造用来发送的群内的或好友的引用回复.
  *
  * 可以引用一条群消息并发送给一个好友, 或是引用好友消息发送给群.
  * 可以引用自己发出的消息. 详见 [MessageReceipt.quote]
  *
  * 总是使用 [quote] 来构造这个实例.
  */
-open class QuoteReply @MiraiInternalAPI constructor(val source: MessageSource) : Message {
+open class QuoteReply
+@MiraiInternalAPI constructor(val source: MessageSource) : Message, MessageContent {
     companion object Key : Message.Key<QuoteReply>
 
     override fun toString(): String = ""
 }
 
 /**
- * 群内的引用回复.
+ * 用于发送的引用回复.
  * 总是使用 [quote] 来构造实例.
  */
 @UseExperimental(MiraiInternalAPI::class)
-class QuoteReplyToSend @MiraiInternalAPI constructor(source: MessageSource, val sender: QQ) : QuoteReply(source) {
+class QuoteReplyToSend
+@MiraiInternalAPI constructor(source: MessageSource, val sender: QQ) : QuoteReply(source) {
     fun createAt(): At = At(sender as Member)
 }
 
diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/XML.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/XML.kt
index 83bd973a5..fb01e7c6c 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/XML.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/XML.kt
@@ -23,8 +23,8 @@ import kotlin.jvm.JvmName
  *
  * @see buildXMLMessage
  */
-inline class XMLMessage(val stringValue: String) : Message,
-    SingleOnly {
+@MiraiExperimentalAPI
+inline class XMLMessage(val stringValue: String) : Message, MessageContent {
     override fun followedBy(tail: Message): Nothing = error("XMLMessage Message cannot be followed")
     override fun toString(): String = stringValue
 }
diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/builder.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/builder.kt
index d2d11b445..86060a517 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/builder.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/builder.kt
@@ -22,8 +22,10 @@ inline fun buildMessageChain(block: MessageChainBuilder.() -> Unit): MessageChai
 }
 
 class MessageChainBuilder @JvmOverloads constructor(
-    private val container: MutableList<Message> = mutableListOf()
-) : MutableList<Message> by container, Appendable {
+    private val container: MutableCollection<Message> = mutableListOf()
+) : MutableCollection<Message> by container, Appendable {
+    constructor(initialSize: Int) : this(ArrayList<Message>(initialSize))
+
     operator fun Message.unaryPlus() {
         add(this)
     }
diff --git a/mirai-core/src/jvmTest/kotlin/net/mamoe/mirai/utils/LockFreeLinkedListTest.kt b/mirai-core/src/jvmTest/kotlin/net/mamoe/mirai/utils/LockFreeLinkedListTest.kt
index 7de786955..de4c3b195 100644
--- a/mirai-core/src/jvmTest/kotlin/net/mamoe/mirai/utils/LockFreeLinkedListTest.kt
+++ b/mirai-core/src/jvmTest/kotlin/net/mamoe/mirai/utils/LockFreeLinkedListTest.kt
@@ -56,6 +56,7 @@ internal class LockFreeLinkedListTest {
         //}
     }
 
+    @Suppress("UNREACHABLE_CODE", "DeferredResultUnused")
     @Test
     fun `so many concurrent add remove and foreach`() = runBlocking {
         return@runBlocking // 测试通过了, 加快速度. 因为 kotlin 一些其他 bug
diff --git a/mirai-plugins/image-sender/src/main/java/net/mamoe/mirai/imageplugin/ImageSenderMain.kt b/mirai-plugins/image-sender/src/main/java/net/mamoe/mirai/imageplugin/ImageSenderMain.kt
index 9bf69d9a9..2e575f86d 100644
--- a/mirai-plugins/image-sender/src/main/java/net/mamoe/mirai/imageplugin/ImageSenderMain.kt
+++ b/mirai-plugins/image-sender/src/main/java/net/mamoe/mirai/imageplugin/ImageSenderMain.kt
@@ -12,17 +12,17 @@ package net.mamoe.mirai.imageplugin
 import kotlinx.coroutines.*
 import net.mamoe.mirai.console.plugins.Config
 import net.mamoe.mirai.console.plugins.ConfigSection
+import net.mamoe.mirai.console.plugins.PluginBase
+import net.mamoe.mirai.contact.Contact
 import net.mamoe.mirai.event.events.BotOnlineEvent
 import net.mamoe.mirai.event.subscribeAlways
 import net.mamoe.mirai.event.subscribeMessages
-import net.mamoe.mirai.console.plugins.PluginBase
-import net.mamoe.mirai.contact.Contact
 import net.mamoe.mirai.message.data.Image
 import net.mamoe.mirai.message.uploadAsImage
 import net.mamoe.mirai.utils.MiraiExperimentalAPI
 import org.jsoup.Jsoup
 import java.io.File
-import kotlin.random.Random
+import java.net.URL
 
 class ImageSenderMain : PluginBase() {
 
@@ -60,7 +60,6 @@ class ImageSenderMain : PluginBase() {
                         reply(e.message ?: "unknown error")
                     }
                 }
-
             }
         }
     }
@@ -84,16 +83,21 @@ class ImageSenderMain : PluginBase() {
 
     override fun onLoad() {
         logger.info("loading local image data")
+
         try {
-            images = Config.load(this.javaClass.classLoader.getResource("data.yml")!!.path!!)
+            images = Config.load(getResources(fileName = "data.yml")!!, "yml")
         } catch (e: Exception) {
+            e.printStackTrace()
             logger.info("无法加载本地图片")
         }
         logger.info("本地图片版本" + images.getString("version"))
-        logger.info("Normal * " + images.getList("normal").size)
-        logger.info("R18    * " + images.getList("R18").size)
+        r18 = images.getConfigSectionList("R18")
+        normal = images.getConfigSectionList("normal")
+        logger.info("Normal * " + normal.size)
+        logger.info("R18    * " + r18.size)
     }
 
+
     override fun onDisable() {
 
     }