code: public MessageIDEnvelope sendMessage(Message data) throws ApiException {
          ApiResponse<MessageIDEnvelope> resp = sendMessageWithHttpInfo(data);
          return resp.getData();
      }
docs: Send Message
  Send a message
  @param data Message object that is passed in the body (required)
  @return MessageIDEnvelope
  @throws ApiException If fail to call the API, e.g. server error or cannot deserialize the response body