.
	 */
	public static function set_is_syncing( $is_syncing ) {
		self::$is_syncing = $is_syncing;
	}

	/**
	 * Whether we are currently sending sync items.
	 *
	 * @access public
	 * @static
	 *
	 * @return boolean Whether we are currently sending sync items.
	 */
	public static function is_sending() {
		return (bool) self::$is_sending;
	}

	/**
	 * Set the sending state.
	 *
	 * @access public
	 * @static
	 *
	 * @param boolean $is_sending Whether we are currently sending sync items.
	 */
	public static function set_is_sending( $is_sending ) {
		self::$is_sending = $is_sending;
	}

	/**
	 * Whether should send from the queue
	 *
	 * @access public
	 * @static
	 *
	 * @param string $queue_id The queue identifier.
	 *
	 * @return boolean Whether sync is enabled.
	 */
	public static function is_sender_enabled( $queue_id ) {
		return (bool) self::get_setting( $queue_id . '_sender_enabled' );
	}

	/**
	 * Whether checksums are enabled.
	 *
	 * @access public
	 * @static
	 *
	 * @return boolean Whether sync is enabled.
	 */
	public static function is_checksum_enabled() {
		return ! (bool) self::get_setting( 'checksum_disable' );
	}

	/**
	 * Whether dedicated Sync flow is enabled.
	 *
	 * @access public
	 * @static
	 *
	 * @return boolean Whether dedicated Sync flow is enabled.
	 */
	public static function is_dedicated_sync_enabled() {
		return (bool) self::get_setting( 'dedicated_sync_enabled' );
	}

	/**
	 * Whether custom queue table is enabled.
	 *
	 * @access public
	 * @static
	 *
	 * @return boolean Whether custom queue table is enabled.
	 */
	public static function is_custom_queue_table_enabled() {
		return (bool) self::get_setting( 'custom_queue_table_enabled' );
	}
}