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