presto-thrift/src/main/java/io/prestosql/plugin/thrift/ThriftSplitManager.java/ThriftSplitSource/close
class ThriftSplitSource:        @Override
        public void close()
        {
            Future<?> currentFuture = future.getAndSet(null);
            if (currentFuture != null) {
                currentFuture.cancel(true);
            }
        }