presto-thrift/src/main/java/io/prestosql/plugin/thrift/ThriftIndexPageSource.java/ThriftIndexPageSource/close
class ThriftIndexPageSource:    @Override
    public void close()
    {
        // cancel futures if available
        cancelQuietly(splitFuture);
        dataRequests.forEach(ThriftIndexPageSource::cancelQuietly);
    }