code: public REQ deserializeRequest(final ByteBuf buf) {
  		Preconditions.checkNotNull(buf);
  		return requestDeserializer.deserializeMessage(buf);
  	}
docs: De-serializes the request sent to the
  {@link org.apache.flink.queryablestate.network.AbstractServerBase}.
  <pre>
  <b>The buffer is expected to be at the request position.</b>
  </pre>
  @param buf	The {@link ByteBuf} containing the serialized request.
  @return		The request.