Motivation:

To be a comprehensive library, all commands should be implemented, even if they are highly discouraged. Sorted Set's collection of commands were missing `bzpopmin` and `bzpopmax`.

Modifications:

`bzpopmin` and `bzpopmax` are supported with defaults and overloads for an easier API.
`RedisClient.channel` is now `internal` to have access during testing for bypassing normal guards for closing connections.

Result:

Users now have access to `bzpopmin` and `bzpopmax` commands.