presto-memory-context/src/main/java/io/prestosql/memory/context/ChildAggregatedMemoryContext.java/ChildAggregatedMemoryContext/ChildAggregatedMemoryContext
class ChildAggregatedMemoryContext:    ChildAggregatedMemoryContext(AggregatedMemoryContext parentMemoryContext)
    {
        verify(parentMemoryContext instanceof AbstractAggregatedMemoryContext);
        this.parentMemoryContext = (AbstractAggregatedMemoryContext) requireNonNull(parentMemoryContext, "parentMemoryContext is null");
    }