presto-main/src/main/java/io/prestosql/operator/OperatorContext.java/OperatorContext/aggregateSystemMemoryContext
class OperatorContext:    public AggregatedMemoryContext aggregateSystemMemoryContext()
    {
        return new InternalAggregatedMemoryContext(operatorMemoryContext.aggregateSystemMemoryContext(), memoryFuture, this::updatePeakMemoryReservations, false);
    }