code: public function send( $recipient, $message, $sendername = null )
      {
  
      	$recipients = explode( ',', $recipient );
      	if( count( $recipients ) > 1000 )
  	    {
  	    	throw new \Exception( 'API is limited to sending to 1000 recipients at a time' );
  	    }
  
          $params = [
  			'form_params' => [
  				'apikey' =>  $this->apikey,
  				'message' => $message,
  				'number' => $recipient,
  				'sendername' => $this->senderName
  			]
          ];
  
          if( $sendername != null )
          {
              $params[ 'form_params' ][ 'sendername' ] = $sendername;
          }
  
          $response = $this->client->post('messages', $params );
  
          return $response->getBody();
      }
docs: Send SMS message(s)
  
  @param $recipient
  @param $message - The message you want to send
  @param null $sendername
  @return StreamInterface
  @throws \Exception
  @internal param $number - The recipient phone number(s)
  @internal param null $senderId - Optional Sender ID (defaults to initialized value or SEMAPHORE)
  @internal param bool|false $bulk - Optional send as bulk