An LRU Cache
An iterator that moves out of a FrameCache.
An iterator over the entries of a FrameCache.
An iterator over mutables entries of a FrameCache.
A smarter pointer help us to share resource in application, and it’ use a
cheap way to compare if two resource is same one.
A single-thread smart pointer with strong reference count only.
This is a simplified version of std::rc::Sc with the weak reference count.
Use it when you are sure that there is no cycle in the reference graph or in
a inner resource manage that will break the cycle by itself.