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