code: Channel getChannel() throws ConnectionFailedException {
          Channel ch = channel.get();
          if (ch == null) {
              throw new ConnectionFailedException("Connection to " + connectionName + " is not established.");
          }
          return ch;
      }
docs: Fetch the netty channel. If {@link Channel} is null then throw a ConnectionFailedException.
  @return  The current {@link Channel}
  @throws ConnectionFailedException Throw if connection is not established.