presto-main/src/main/java/io/prestosql/memory/MemoryPool.java/MemoryPool/getTaggedMemoryAllocations
class MemoryPool:    @VisibleForTesting
    synchronized Map<QueryId, Map<String, Long>> getTaggedMemoryAllocations()
    {
        return ImmutableMap.copyOf(taggedMemoryAllocations);
    }