presto-main/src/main/java/io/prestosql/operator/OperatorContext.java/OperatorSpillContext/close
class OperatorSpillContext:        @Override
        public void close()
        {
            // Only products of SpillContext.newLocalSpillContext() should be closed.
            throw new UnsupportedOperationException(format("%s should not be closed directly", getClass()));
        }