Cached methods using quickrand_cache need to be initialised first

[okeuday]

Cached methods using quickrand_cache need to be initialised first

[okeuday]

@louiscb quickrand and uuid should be treated as separate Erlang/OTP applications, so it is best to not add to the uuid Erlang module with quickrand initialization details. If more information is added to the README file, that would help people avoid any problems (there is already info about quickrand:seed/0 in the current README). Feel free to do a pull request with a README addition for quickrand_cache initialization details.

[louiscb]

Ok. What's the intended use case of the cached v4? Since we have to do the quickrand initialisation per process, it adds a lot of overhead and increases the execution time of the uuid generation massively.

[okeuday]

I added a description in quickrand_cache for its usage.
https://github.com/okeuday/quickrand/blob/2e82140b30bbf548726f98b836bc469cabcfb075/src/quickrand_cache.erl#L7-L18
I also modified the README change to provide more details.
The usage of quickrand_cache would want the cached random data to stick around a long time, so the Erlang process should be long-lived if the init function is used. Otherwise, you should be using the new function as described in the new README info.