mpyw\Co\Internal\GeneratorContainer::getYieldKey PHP Метод

    public function getYieldKey()
    {
        return $this->yieldKey;
    }

 /**
  * Handle resolving generators already done.
  * @param  GeneratorContainer $gc
  * @return PromiseInterface
  */
 private function processGeneratorContainerDone(GeneratorContainer $gc)
 {
     // If exception has been thrown in generator, we have to propagate it as rejected value
     if ($gc->thrown()) {
         return new RejectedPromise($gc->getReturnOrThrown());
     }
     // Now we normalize returned value
     $returned = YieldableUtils::normalize($gc->getReturnOrThrown(), $gc->getYieldKey());
     $yieldables = YieldableUtils::getYieldables($returned, [], $this->runners);
     // If normalized value contains yieldables, we have to chain resolver
     if ($yieldables) {
         $deferred = new Deferred();
         return $this->promiseAll($yieldables, true)->then(YieldableUtils::getApplier($returned, $yieldables, [$deferred, 'resolve']), [$deferred, 'reject'])->then(function () use($yieldables, $deferred) {
             $this->runners = array_diff_key($this->runners, $yieldables);
             return $deferred->promise();
         });
     }
     // Propagate normalized returned value
     return new FulfilledPromise($returned);
 }