presto-main/src/main/java/io/prestosql/operator/exchange/LocalExchange.java/LocalExchange/sinkFactoryClosed
class LocalExchange:    private void sinkFactoryClosed(LocalExchangeSinkFactory sinkFactory)
    {
        checkNotHoldsLock(this);

        synchronized (this) {
            openSinkFactories.remove(sinkFactory);
        }
        checkAllSinksComplete();
    }