Testing WP CLI and WP Gears. WP Gears integrates Gearman with WordPress for asynchronous task running. WP Gears is available at https://github.com/10up/WP-Gears

wp-cli-gears.php

<?php
/*
Plugin Name: WP CLI GEARS
Version: 0.0.2
Description: Testing WP CLI and WP Gears
Author: Per Soderlind
Author URI: https://soderlind.no
Plugin URI: https://gist.github.com/soderlind/a27527c3ed6545f594d7
License: GPL
*/
function wp_cli_gears_plugin_init() {
	if ( defined( 'WP_CLI' ) && WP_CLI ) {
		/**
		 * Test WP Gears using WP CLI
		 */
		class WP_Gears_Command extends WP_CLI_Command {
			/**
			 * Test wp cli and wp gears
			 * ## OPTIONS
			 *
			 * <file>
			 * : Path to output file
			 *
			 * @synopsis <file>
			 */
			function mytest( $args, $assoc_args ) {
				list( $file ) = $args;
				wp_async_task_add( 'wp_cli_gears_worker', array( 'file' => $file ) );
				WP_CLI::success( 'Done!' );
			}
		}
		WP_CLI::add_command( 'wp-gears-test', 'WP_Gears_Command' );
	}
}
if ( defined( 'WP_CLI' ) ) {
	add_action( 'plugins_loaded', 'wp_cli_gears_plugin_init' );
}
/**
 * Worker Class, NOTE, this class is must be outside "if ( defined('WP_CLI') && WP_CLI ) {}"
 */
class WP_Gears_Command_Worker {
	/**
	 * Worker callback function
	 *
	 * @param  array $args parameters sent to the function. added using wp_async_task_add()
	 */
	static function wp_cli_gears_worker_callback( $args ) {
		//must have write access to $args['file']
		file_put_contents( $args['file'], 'Time: ' . time() . "\n", FILE_APPEND );
	}
}
add_action( 'wp_cli_gears_worker', array( 'WP_Gears_Command_Worker', 'wp_cli_gears_worker_callback' ) );