Noptin_Background_Sync::get_unsynced_subscriber()

	public function get_unsynced_subscriber() {

		$query = new Noptin_Subscriber_Query(
			array(
				'meta_key'	    => 'wp_user_id',
				'meta_compare'  => 'NOT EXISTS',
				'number'        => 1,
				'fields'        => 'id',
				'count_total'   => false,
			)
		);

		$subscriber = $query->get_results();

		return empty( $subscriber ) ? 0 : $subscriber[0];

	}