send email using gmail api

function send_message($sender, $sender_name, $to_email, $to_name, $subject, $message_text) {
  $message = new Google_Service_Gmail_Message();
  $message->setRaw(rfc822_base64($sender, $to_email, $subject, $message_text));
  $service->users_messages->send("me", $message);
}