Mailgun\Messages\MessageBuilder::addToRecipient PHP Method

    public function addToRecipient($address, $variables = null)
    {
        if ($this->counters['recipients']['to'] > Api::RECIPIENT_COUNT_LIMIT) {
            throw new TooManyParameters(ExceptionMessages::TOO_MANY_PARAMETERS_RECIPIENT);
        }
        $this->addRecipient('to', $address, $variables);
        return end($this->message['to']);
    }

 /**
  * Add a recipient to the message.
  *
  * @param string|array $address
  * @param string       $name
  * @param array        $variables
  *
  * @return \Bogardo\Mailgun\Mail\Message
  */
 public function to($address, $name = "", array $variables = [])
 {
     if (is_array($address)) {
         foreach ($address as $email => $variables) {
             $this->variables[$email] = $variables;
             $name = isset($variables['name']) ? $variables['name'] : null;
             $this->messageBuilder->addToRecipient($email, ['full_name' => $name]);
         }
     } else {
         if (!empty($variables)) {
             $this->variables[$address] = $variables;
         }
         $this->messageBuilder->addToRecipient($address, ['full_name' => $name]);
     }
     return $this;
 }