code: public final ChannelFuture processHandshake(final Channel channel, HttpResponse response) {
          return processHandshake(channel, response, channel.newPromise());
      }
docs: Process the opening handshake initiated by {@link #handshake}}.
  
  @param channel
  Channel
  @param response
  HTTP response containing the closing handshake details
  @return future
  the {@link ChannelFuture} which is notified once the handshake completes.