[Discussion] Async Version of Backends Implementation

If we were to add async support, which option is better 1 or 2? 1. Add a new class parameter `async=True`, switch between normal and async client based on it, and implement async functions prefixed with the letter `a` then function name. ex. `aget_many()` or `aset()` 2. Duplicate the entire class and add implementation for async functions without prefixing the function names. Instead, the class name will start with the word "`Async`". ex. `AsyncSimpleCache` etc.. I would like to know if anyone has better suggestions or modifications too