Update progress during upload large bodies, close AsyncHttpClient#728

Motivation:

`BodyChunkedInput` does not update progress member, it always stays zero.
Thus `ProgressAsyncHandler#onContentWriteProgress` receives zeroes in amount and current parameters. Users sees data is being sent but has no information about exact amount of data has been written to channel.

Modifications:

`BodyChunkedInput` was modified to update progress.
`WriteProgressListener` was modified to ignore zero progress. It happens due to non-blocking nature of network writes. We just ignore callbacks when there was no progress at all.

Result:

Progress is updated each time bytes are phisically written to channel.
Callbacks are triggered with actual amount of data written.

Author: odiszapc

client/src/main/java/org/asynchttpclient/netty/request/WriteProgressListener.java

@@ -45,7 +45,9 @@ public void operationProgressed(ChannelProgressiveFuture f, long progress, long
             if (total < 0) {
                 total = expectedTotal;
             }
-            progressAsyncHandler.onContentWriteProgress(progress - lastLastProgress, progress, total);
+            if (progress != lastLastProgress) {
+                progressAsyncHandler.onContentWriteProgress(progress - lastLastProgress, progress, total);
+            }
         }
     }
 }

client/src/main/java/org/asynchttpclient/netty/request/body/BodyChunkedInput.java

@@ -57,6 +57,7 @@ public ByteBuf readChunk(ByteBufAllocator alloc) throws Exception {
 
         ByteBuf buffer = alloc.buffer(chunkSize);
         Body.BodyState state = body.transferTo(buffer);
+        progress += buffer.writerIndex();
         switch (state) {
         case STOP:
             endOfInput = true;