Rename Discard singleton

Author: slandelle

client/src/main/java/org/asynchttpclient/netty/DiscardEvent.java

@@ -17,5 +17,5 @@
  * Simple marker for stopping publishing bytes
  */
 public enum DiscardEvent {
-    INSTANCE
+    DISCARD
 }

client/src/main/java/org/asynchttpclient/netty/channel/Channels.java

@@ -40,7 +40,7 @@ public static void setAttribute(Channel channel, Object o) {
     }
 
     public static void setDiscard(Channel channel) {
-        setAttribute(channel, DiscardEvent.INSTANCE);
+        setAttribute(channel, DiscardEvent.DISCARD);
     }
 
     public static boolean isChannelValid(Channel channel) {

client/src/main/java/org/asynchttpclient/netty/handler/AsyncHttpClientHandler.java

@@ -102,7 +102,7 @@ public void channelRead(final ChannelHandlerContext ctx, Object msg) throws Exce
                     ctx.pipeline().remove(publisher);
                     Channels.setDiscard(channel);
                 }
-            } else if (attribute != DiscardEvent.INSTANCE) {
+            } else if (attribute != DiscardEvent.DISCARD) {
                 // unhandled message
                 logger.debug("Orphan channel {} with attribute {} received message {}, closing", channel, attribute, msg);
                 Channels.silentlyCloseChannel(channel);