Not completely sure if it's worth having for 8.0, but opening this to share the target I'm trying to reach.
-- v3: ntdll: Implement Low Fragmentation Heap. ntdll: Introduce per-thread free lists for heap blocks. ntdll: Introduce a new BLOCK_FLAG_SPLIT heap block flag. ntdll: Introduce a new subheap thread affinity field. ntdll: Introduce a new heap block_init_used helper. ntdll: Introduce a new heap free_list_init helper. ntdll: Count allocations and automatically enable LFH. ntdll: Implement HeapCompatibilityInformation.