Netty ChannelManager.tryToOfferChannelToPool makes channel available for selection prematurely

AsyncHttpClient#834

Author: maxpower-artvandelay

providers/netty3/src/main/java/org/asynchttpclient/providers/netty3/channel/ChannelManager.java

@@ -284,10 +284,10 @@ protected String getTargetContentEncoding(String contentEncoding) throws Excepti
     public final void tryToOfferChannelToPool(Channel channel, boolean keepAlive, String partition) {
         if (channel.isConnected() && keepAlive && channel.isReadable()) {
             LOGGER.debug("Adding key: {} for channel {}", partition, channel);
+            Channels.setDiscard(channel);
             channelPool.offer(channel, partition);
             if (maxConnectionsPerHostEnabled)
                 channelId2KeyPool.putIfAbsent(channel.getId(), partition);
-            Channels.setDiscard(channel);
         } else {
             // not offered
             closeChannel(channel);