A lazy-initialized object pool. Provides a sharable pool where objects are initialized on demand. The pool works by providing Futures which allow for usage with async/await (untested) and threading as well.

See tests for examples of usage

• Reworked most of the package to make it async-first. Having the factory methods being synchronous would force switching from async - to sync - to async which didn't work in many cases. The interface changed significantly.
• Locking is now using async-aware mutexes.
• Releasing objects back to the pool needs to be done outside of Drop (until AsyncDrop becomes a thing). Introduced a get macro to be used as the main means of acquiring and using an item.

• Allow marking an object as tainted through the Pooled wrapper. This drops the item from the pool instead of releasing it.

• Migrate to std futures.

• Introduce mutable dereferencing

• Minor fixes and switch to VecDeque

• Deprecated all previous version due to misusing Future trait
• Allow definition of a factory using closures. This adds the overhead of needing a box for function references as well