We explain, in this file, how the allocators work in this library
The allocator is separated into 3 different subclasses, all derived from the base interface INativeAllocator, the subclasses are respectively:
BumpPointerNativeAllocatorMemoryMappedFileAllocatorDelegatedMultipleAllocator
these 3 allocators cooperate closely and are managed by a single class called MemoryMappedFileAllocatorManager.
In summary, the cache layout is as follows: the cache itself can be separated into several files each of which is an instance of the memory mapped file, and each memory mapped file is refined into different chunks, now, for each memory mapped file, there is an allocator responsible for allocating the chunks, similarly, there is also a manager for managing the memory mapped files, thus it forms naturally a tree-likes structure of allocators.