presto-main/src/main/java/io/prestosql/operator/Driver.java/Driver/tryLock
class Driver:        public boolean tryLock(long timeout, TimeUnit unit)
                throws InterruptedException
        {
            checkState(!lock.isHeldByCurrentThread(), "Lock is not reentrant");
            boolean acquired = lock.tryLock(timeout, unit);
            if (acquired) {
                setOwner();
            }
            return acquired;
        }