The mem hook consumes the orphan tracker by default. If the thread does not attach other trackers, by default all consumption will be passed to the process tracker through the orphan tracker.
In real time, consumption of all other trackers + orphan tracker consumption = process tracker consumption.
Ideally, all threads are expected to attach to the specified tracker, so that "all memory has its own ownership", and the consumption of the orphan mem tracker is close to 0, but greater than 0.
The memory value automatically tracked by the tcmalloc hook in the DeltaWriter is smaller than the value recorded manually in the memtable, because the first 4096-byte Chunk requested by each MemPool when the memtable is initialized is not tracked to the DeltaWriter by the hook.
The values of the two are not equal, causing the mem_consumption() == _mem_table->memory_usage branch judgment to fail.
