PHP8.0中的异步迭代器

class MyAsyncIterator implements AsyncIteratorInterface
{
    public function getAsyncIterator(): AsyncIteratorInterface
    {
        return $this;
    }
 
    public async function fetchAsync(): Promise
    {
        return await $this->getNextDataFromSource();
    }
 
    private async function getNextDataFromSource()
    {
        //异步加载数据
        return 'next data';
    }
}

class MyAsyncIterable implements AsyncIteratorInterface {
    private int $max;
    
    public function __construct(int $max) {
        $this->max = $max;
    }
    
    public function getAsyncIterator(): AsyncIteratorInterface {
        return $this;
    }
    
    public async function fetchAsync(): Promise {
        if ($this->max <= 0) {
            return null;
        }
        
        $toDelay = rand(1, 3);
        $this->max -= $toDelay;
        await new ReactPromiseTimerInterval($toDelay * 1000);
        return $this->max;
    }
}
 
class App {
    public static async function main(Array $args) {
        $asyncIterable = new MyAsyncIterable(10);
        foreach ($asyncIterable as $number) {
            echo "Delay: $number 
";
        }
    }
}
 
App::main($argv)->done();

Delay: 7 
Delay: 5 
Delay: 2 
Delay: -1