Use default ByteBufAllocator instead of context's one, see AsyncHttpClient#1029

Author: slandelle

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

@@ -15,6 +15,7 @@
 
 import static org.asynchttpclient.util.Assertions.assertNotNull;
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufAllocator;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.stream.ChunkedInput;
 
@@ -47,7 +48,7 @@ public ByteBuf readChunk(ChannelHandlerContext ctx) throws Exception {
         if (endOfInput)
             return null;
 
-        ByteBuf buffer = ctx.alloc().buffer(chunkSize);
+        ByteBuf buffer = ByteBufAllocator.DEFAULT.buffer(chunkSize);
         Body.BodyState state = body.transferTo(buffer);
         switch (state) {
             case STOP: