code: public function send($recipientId, Message $message)
      {
          $body = new Body;
  
          $body->setRecipient($recipientId);
          $body->setMessage($message);
  
          return $this->sendApi($body);
      }
docs: Send message
  
  @param int $recipientId Recipient id
  @param Message $message
  
  @return array