pocketmine\inventory\SimpleTransactionQueue::execute PHP Method

    public function execute()
    {
        /** @var Transaction[] */
        $failed = [];
        while (!$this->transactionsToRetry->isEmpty()) {
            //Some failed transactions are waiting from the previous execution to be retried
            $this->transactionQueue->enqueue($this->transactionsToRetry->dequeue());
        }
        if (!$this->transactionQueue->isEmpty()) {
            $this->player->getServer()->getPluginManager()->callEvent($ev = new InventoryTransactionEvent($this));
        } else {
            return;
        }
        while (!$this->transactionQueue->isEmpty()) {
            $transaction = $this->transactionQueue->dequeue();
            if ($ev->isCancelled()) {
                $this->transactionCount -= 1;
                $transaction->sendSlotUpdate($this->player);
                //Send update back to client for cancelled transaction
                unset($this->inventories[spl_object_hash($transaction)]);
                continue;
            } elseif (!$transaction->execute($this->player)) {
                $transaction->addFailure();
                if ($transaction->getFailures() >= self::DEFAULT_ALLOWED_RETRIES) {
                    /* Transaction failed completely after several retries, hold onto it to send a slot update */
                    $this->transactionCount -= 1;
                    $failed[] = $transaction;
                } else {
                    /* Add the transaction to the back of the queue to be retried on the next tick */
                    $this->transactionsToRetry->enqueue($transaction);
                }
                continue;
            }
            $this->transactionCount -= 1;
            $transaction->setSuccess();
            $transaction->sendSlotUpdate($this->player);
            unset($this->inventories[spl_object_hash($transaction)]);
        }
        foreach ($failed as $f) {
            $f->sendSlotUpdate($this->player);
            unset($this->inventories[spl_object_hash($f)]);
        }
    }