public function toArray()
{
$this->checkRecipient();
return ['recipient' => ['id' => $this->recipient_id], 'message' => ['attachment' => ['type' => 'template', 'payload' => ['template_type' => 'button', 'text' => MessengerUtils::checkStringLengthAndEncoding($this->text, 320, 'UTF-8'), 'buttons' => MessengerUtils::checkArraySize($this->buttons, 3)]]]];
}