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