public function consume()
    {
        foreach ($this->untils as $id => $until) {
            $diff = $until - microtime(true);
            if ($diff > 0.0 || !isset($this->deferreds[$id])) {
                continue;
            }
            $deferred = $this->deferreds[$id];
            unset($this->deferreds[$id], $this->untils[$id]);
            $deferred->resolve(null);
        }
    }