presto-memory-context/src/main/java/io/prestosql/memory/context/AggregatedMemoryContext.java/AggregatedMemoryContext/newRootAggregatedMemoryContext
class AggregatedMemoryContext:    static AggregatedMemoryContext newRootAggregatedMemoryContext(MemoryReservationHandler reservationHandler, long guaranteedMemoryInBytes)
    {
        return new RootAggregatedMemoryContext(reservationHandler, guaranteedMemoryInBytes);
    }