Don't use replace but addAfter+remove so that first frame is not lost, close AsyncHttpClient#471

Author: Stephane Landelle

providers/netty/src/main/java/org/asynchttpclient/providers/netty/channel/ChannelManager.java

@@ -385,8 +385,10 @@ public void upgradeProtocol(ChannelPipeline pipeline, String scheme, String host
         else
             pipeline.addFirst(HTTP_HANDLER, newHttpClientCodec());
 
-        if (isWebSocket(scheme))
-            pipeline.replace(HTTP_PROCESSOR, WS_PROCESSOR, wsProcessor);
+        if (isWebSocket(scheme)) {
+            pipeline.addAfter(HTTP_PROCESSOR, WS_PROCESSOR, wsProcessor);
+            pipeline.remove(HTTP_PROCESSOR);
+        }
     }
 
     public String getPoolKey(NettyResponseFuture<?> future) {
@@ -416,7 +418,8 @@ public Bootstrap getBootstrap(UriComponents uri, boolean useProxy, boolean useSS
     }
 
     public void upgradePipelineForWebSockets(ChannelPipeline pipeline) {
-        pipeline.replace(HTTP_HANDLER, WS_ENCODER_HANDLER, new WebSocket08FrameEncoder(true));
+        pipeline.addAfter(HTTP_HANDLER, WS_ENCODER_HANDLER, new WebSocket08FrameEncoder(true));
+        pipeline.remove(HTTP_HANDLER);
         pipeline.addBefore(WS_PROCESSOR, WS_DECODER_HANDLER, new WebSocket08FrameDecoder(false, false, 10 * 1024));
     }