Fix SafeStateObserver: add missing override beforeStateChanged

mirai-core/src/commonMain/kotlin/network/handler/state/SafeStateObserver.kt

@@ -1,10 +1,10 @@
 /*
- * Copyright 2019-2021 Mamoe Technologies and contributors.
+ * Copyright 2019-2022 Mamoe Technologies and contributors.
  *
  * 此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
  * Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
  *
- *  https://github.com/mamoe/mirai/blob/master/LICENSE
+ * https://github.com/mamoe/mirai/blob/dev/LICENSE
  */
 
 package net.mamoe.mirai.internal.network.handler.state
@@ -31,6 +31,21 @@ internal class SafeStateObserver(
         return "SafeStateObserver(delegate=$delegate)"
     }
 
+    override fun beforeStateChanged(
+        networkHandler: NetworkHandlerSupport,
+        previous: NetworkHandlerSupport.BaseStateImpl,
+        new: NetworkHandlerSupport.BaseStateImpl
+    ) {
+        try {
+            delegate.beforeStateChanged(networkHandler, previous, new)
+        } catch (e: Throwable) {
+            logger.error(
+                { "Internal error: exception in StateObserver $delegate" },
+                ExceptionInStateObserverException(e)
+            )
+        }
+    }
+
     override fun stateChanged(
         networkHandler: NetworkHandlerSupport,
         previous: NetworkHandlerSupport.BaseStateImpl,