docs: public SendMessageResult sendMessage(Integer version, String targetType, String targetId,
                                           String fromType, String fromId, MessageType messageType, MessageBody messageBody)
              throws APIConnectionException, APIRequestException {
          MessagePayload payload = MessagePayload.newBuilder()
                  .setVersion(version)
                  .setTargetType(targetType)
                  .setTargetId(targetId)
                  .setFromType(fromType)
                  .setFromId(fromId)
                  .setMessageType(messageType)
                  .setMessageBody(messageBody)
                  .build();
          return _messageClient.sendMessage(payload);
      }