presto-main/src/main/java/io/prestosql/memory/MemoryPool.java/MemoryPool/getInfo
class MemoryPool:    public synchronized MemoryPoolInfo getInfo()
    {
        Map<QueryId, List<MemoryAllocation>> memoryAllocations = new HashMap<>();
        for (Entry<QueryId, Map<String, Long>> entry : taggedMemoryAllocations.entrySet()) {
            List<MemoryAllocation> allocations = new ArrayList<>();
            if (entry.getValue() != null) {
                entry.getValue().forEach((tag, allocation) -> allocations.add(new MemoryAllocation(tag, allocation)));
            }
            memoryAllocations.put(entry.getKey(), allocations);
        }
        return new MemoryPoolInfo(maxBytes, reservedBytes, reservedRevocableBytes, queryMemoryReservations, memoryAllocations, queryMemoryRevocableReservations);
    }