TaskQueueInterface.php

<?php

declare (strict_types=1);
namespace GuzzleHttp\Promise;

interface TaskQueueInterface {
    
    /**
     * Returns true if the queue is empty.
     */
    public function isEmpty() : bool;
    
    /**
     * Adds a task to the queue that will be executed the next time run is
     * called.
     */
    public function add(callable $task) : void;
    
    /**
     * Execute all of the pending task in the queue.
     */
    public function run() : void;

}