1<?php
2
3namespace GuzzleHttp\Promise;
4
5interface TaskQueueInterface
6{
7    /**
8     * Returns true if the queue is empty.
9     *
10     * @return bool
11     */
12    public function isEmpty();
13
14    /**
15     * Adds a task to the queue that will be executed the next time run is
16     * called.
17     */
18    public function add(callable $task);
19
20    /**
21     * Execute all of the pending task in the queue.
22     */
23    public function run();
24}
25