$retry_time = get_option( Actions::RETRY_AFTER_PREFIX . 'immediate-send' );
		if ( $retry_time ) {
			// If expired delete but don't send. Send will occurr in new request to avoid race conditions.
			if ( microtime( true ) > $retry_time ) {
				update_option( Actions::RETRY_AFTER_PREFIX . 'immediate-send', false, false );
			}
			return false;
		}

		// Obtain send Lock.
		$lock            = new Lock();
		$lock_expiration = $lock->attempt( self::LOCK_NAME );

		// Return if unable to obtain lock.
		if ( false === $lock_expiration ) {
			return;
		}

		// Send Full Sync actions.
		$success = $this->send();

		// Remove lock.
		if ( $success ) {
			$lock->remove( self::LOCK_NAME, $lock_expiration );
		}
	}

	/**
	 * Immediately send the next items to full sync.
	 *
	 * @access public
	 */
	public function send() {
		$config = $this->get_status()['config'];

		$max_duration = Settings::get_setting( 'full_sync_send_duration' );
		$send_until   = microtime( true ) + $max_duration;

		$progress = $this->get_status()['progress'];

		foreach ( $this->get_remaining_modules_to_send() as $module ) {
			$progress[ $module->name() ] = $module->send_full_sync_actions( $config[ $module->name() ], $progress[ $module->name() ], $send_until );
			if ( isset( $progress[ $module->name() ]['error'] ) ) {
				unset( $progress[ $module->name() ]['error'] );
				$this->update_status( array( 'progress' => $progress ) );
				return false;
			} elseif ( ! $progress[ $module->name() ]['finished'] ) {
				$this->update_status( array( 'progress' => $progress ) );
				return true;
			}
		}

		$this->send_full_sync_end();
		$this->update_status( array( 'progress' => $progress ) );
		return true;
	}

	/**
	 * Get Modules that are configured to Full Sync and haven't finished sending
	 *
	 * @return array
	 */
	public function get_remaining_modules_to_send() {
		$status = $this->get_status();

		return array_filter(
			Modules::get_modules(),
			/**
			 * Select configured and not finished modules.
			 *
			 * @return bool
			 * @var $module Module
			 */
			function ( $module ) use ( $status ) {
				// Skip module if not configured for this sync or module is done.
				if ( ! isset( $status['config'][ $module->name() ] ) ) {
					return false;
				}
				if ( ! $status['config'][ $module->name() ] ) {
					return false;
				}
				if ( isset( $status['progress'][ $module->name() ]['finished'] ) ) {
					if ( true === $status['progress'][ $module->name() ]['finished'] ) {
						return false;
					}
				}

				return true;
			}
		);
	}

	/**
	 * Send 'jetpack_full_sync_end' and update 'finished' status.
	 *
	 * @access public
	 */
	public function send_full_sync_end() {
		$range = $this->get_content_range();

		/**
		 * Fires when a full sync ends. This action is serialized
		 * and sent to the server.
		 *
		 * @param string $checksum Deprecated since 7.3.0 - @see https://github.com/Automattic/jetpack/pull/11945/
		 * @param array $range Range of the sync items, containing min and max IDs for some item types.
		 *
		 * @since 4.2.0
		 * @since 7.3.0 Added $range arg.
		 */
		do_action( 'jetpack_full_sync_end', '', $range );
		$this->send_action( 'jetpack_full_sync_end', array( '', $range ) );

		// Setting autoload to true means that it's faster to check whether we should continue enqueuing.
		$this->update_status( array( 'finished' => time() ) );
	}

	/**
	 * Empty Function as we don't close buffers on Immediate Full Sync.
	 *
	 * @param array $actions an array of actions, ignored for queueless sync.
	 */
	public function update_sent_progress_action( $actions ) { } // phpcs:ignore VariableAnalysis.CodeAnalysis.VariableAnalysis.UnusedVariable

}