'theme_mods_' === substr( $args[0], 0, 11 ) ) {
			$this->filter_theme_mods( $args[1] );
			if ( isset( $args[2] ) ) {
				$this->filter_theme_mods( $args[2] );
			}
		}

		// Set value(s) of contentless option to empty string(s).
		if ( $this->is_contentless_option( $args[0] ) ) {
			// Create a new array matching length of $args, containing empty strings.
			$empty    = array_fill( 0, count( $args ), '' );
			$empty[0] = $args[0];
			return $empty;
		}

		return $args;
	}

	/**
	 * Whether a certain option is whitelisted for sync.
	 *
	 * @access public
	 *
	 * @param string $option Option name.
	 * @return boolean Whether the option is whitelisted.
	 */
	public function is_whitelisted_option( $option ) {
		return in_array( $option, $this->options_whitelist, true ) || 'theme_mods_' === substr( $option, 0, 11 );
	}

	/**
	 * Whether a certain option is a contentless one.
	 *
	 * @access private
	 *
	 * @param string $option Option name.
	 * @return boolean Whether the option is contentless.
	 */
	private function is_contentless_option( $option ) {
		return in_array( $option, $this->options_contentless, true );
	}

	/**
	 * Filters out falsy values from theme mod options.
	 *
	 * @access private
	 *
	 * @param array $value Option value.
	 */
	private function filter_theme_mods( &$value ) {
		if ( is_array( $value ) && isset( $value[0] ) ) {
			unset( $value[0] );
		}
	}

	/**
	 * Handle changes in the core site icon and sync them.
	 *
	 * @access public
	 */
	public function jetpack_sync_core_icon() {
		$url = get_site_icon_url();

		require_once JETPACK__PLUGIN_DIR . 'modules/site-icon/site-icon-functions.php';
		// If there's a core icon, maybe update the option.  If not, fall back to Jetpack's.
		if ( ! empty( $url ) && jetpack_site_icon_url() !== $url ) {
			// This is the option that is synced with dotcom.
			\Jetpack_Options::update_option( 'site_icon_url', $url );
		} elseif ( empty( $url ) ) {
			\Jetpack_Options::delete_option( 'site_icon_url' );
		}
	}

	/**
	 * Expand all options within a hook before they are serialized and sent to the server.
	 *
	 * @access public
	 *
	 * @param array $args The hook parameters.
	 * @return array $args The hook parameters.
	 */
	public function expand_options( $args ) {
		if ( $args[0] ) {
			return $this->get_all_options();
		}

		return $args;
	}

	/**
	 * Return Total number of objects.
	 *
	 * @param array $config Full Sync config.
	 *
	 * @return int total
	 */
	public function total( $config ) { // phpcs:ignore VariableAnalysis.CodeAnalysis.VariableAnalysis.UnusedVariable
		return count( Defaults::get_options_whitelist() );
	}

}