Fix a regression in ChannelInboundMessageHandlerAdapter

- Should forward the unsupported message to the next inbound buffer rather than the next outbound buffer.

transport/src/main/java/io/netty/channel/ChannelInboundMessageHandlerAdapter.java

@@ -82,7 +82,7 @@ public abstract class ChannelInboundMessageHandlerAdapter<I>
                 try {
                     if (!isSupported(msg)) {
                         if (out == null) {
-                            out = ctx.nextOutboundMessageBuffer();
+                            out = ctx.nextInboundMessageBuffer();
                         }
                         out.add(msg);
                         unsupportedFound = true;