presto-memory-context/src/main/java/io/prestosql/memory/context/MemoryTrackingContext.java/MemoryTrackingContext/newAggregateSystemMemoryContext
class MemoryTrackingContext:    public AggregatedMemoryContext newAggregateSystemMemoryContext()
    {
        return systemAggregateMemoryContext.newAggregatedMemoryContext();
    }