diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/utils/PlatformUtils.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/utils/PlatformUtils.kt
index c7bea5bbe..5af98c39a 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/utils/PlatformUtils.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/utils/PlatformUtils.kt
@@ -5,12 +5,7 @@ package net.mamoe.mirai.utils
 import com.soywiz.klock.DateTime
 import io.ktor.client.HttpClient
 import io.ktor.client.request.HttpRequestBuilder
-import io.ktor.client.request.post
-import io.ktor.http.HttpStatusCode
-import io.ktor.http.URLProtocol
-import io.ktor.http.userAgent
 import kotlinx.io.core.Input
-import net.mamoe.mirai.contact.GroupId
 
 /**
  * 时间戳
@@ -38,7 +33,7 @@ expect fun md5(byteArray: ByteArray): ByteArray
 /**
  * Hostname 解析 IP 地址
  */
-expect fun solveIpAddress(hostname: String): String
+expect fun solveIpAddress(hostname: String): String // TODO: 2019/10/28 是否有必要?
 
 /**
  * Localhost 解析
@@ -46,80 +41,10 @@ expect fun solveIpAddress(hostname: String): String
 expect fun localIpAddress(): String
 
 /**
- * Provided by Ktor Http
+ * Ktor HttpClient. 不同平台使用不同引擎.
  */
 internal expect val httpClient: HttpClient
 
-/**
- * 上传好友图片
- */
-@Suppress("DuplicatedCode")
-suspend fun httpPostFriendImage(
-    botAccount: UInt,
-    uKeyHex: String,
-    imageInput: Input,
-    inputSize: Long
-): Boolean = (httpClient.postImage(
-    htcmd = "0x6ff0070",
-    uin = botAccount,
-    groupcode = null,
-    imageInput = imageInput,
-    inputSize = inputSize,
-    uKeyHex = uKeyHex
-) as HttpStatusCode).value == 200
-
-/**
- * 上传群图片
- */
-@Suppress("DuplicatedCode")
-suspend fun httpPostGroupImage(
-    botAccount: UInt,
-    groupId: GroupId,
-    uKeyHex: String,
-    imageInput: Input,
-    inputSize: Long
-): Boolean = (httpClient.postImage(
-    htcmd = "0x6ff0071",
-    uin = botAccount,
-    groupcode = groupId,
-    imageInput = imageInput,
-    inputSize = inputSize,
-    uKeyHex = uKeyHex
-) as HttpStatusCode).value == 200
-
-@Suppress("SpellCheckingInspection")
-private suspend inline fun <reified T> HttpClient.postImage(
-    htcmd: String,
-    uin: UInt,
-    groupcode: GroupId?,
-    imageInput: Input,
-    inputSize: Long,
-    uKeyHex: String
-): T = try {
-    post {
-        url {
-            protocol = URLProtocol.HTTP
-            host = "htdata2.qq.com"
-            path("cgi-bin/httpconn")
-
-            parameters["htcmd"] = htcmd
-            parameters["uin"] = uin.toLong().toString()
-
-            if (groupcode != null) parameters["groupcode"] = groupcode.value.toLong().toString()
-
-            parameters["term"] = "pc"
-            parameters["ver"] = "5603"
-            parameters["filesize"] = inputSize.toString()
-            parameters["range"] = 0.toString()
-            parameters["ukey"] = uKeyHex
-
-            userAgent("QQClient")
-        }
-
-        configureBody(inputSize, imageInput)
-    }
-} finally {
-    imageInput.close()
-}
 
+// FIXME: 2019/10/28 这个方法不是很好的实现
 internal expect fun HttpRequestBuilder.configureBody(inputSize: Long, input: Input)
\ No newline at end of file
diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/utils/io/OutputUtils.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/utils/io/OutputUtils.kt
index 86477669b..bf7089f1c 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/utils/io/OutputUtils.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/utils/io/OutputUtils.kt
@@ -26,9 +26,10 @@ fun BytePacketBuilder.writeShortLVByteArray(byteArray: ByteArray) {
 }
 
 
+// will box, but it doesn't matter
 private fun <N : Comparable<N>> N.coerceAtMostOrFail(maximumValue: N): N =
-        if (this > maximumValue) error("value is greater than its expected maximum value $maximumValue")
-        else this
+    if (this > maximumValue) error("value is greater than its expected maximum value $maximumValue")
+    else this
 
 fun BytePacketBuilder.writeShortLVPacket(tag: UByte? = null, lengthOffset: ((Long) -> Long)? = null, builder: BytePacketBuilder.() -> Unit) = with(BytePacketBuilder().apply(builder).build()) {
     if (tag != null) {