php-http/promise/src/Promise.php

<?php
 
namespace Http\Promise;
 
interface Promise
{
    const PENDING = 'pending';
 
    const FULFILLED = 'fulfilled';
 
    const REJECTED = 'rejected';
 
    public function then(callable $onFulfilled = null, callable $onRejected = null);
 
    public function getState();
 
    public function wait($unwrap = true);
}