Encapsulate With `channel` Type
Encapsulate With `channel` Type

Removes the string concatenation littered throughout the RedisBroker
implementation and replaces it with the `channel` type. The `channel`
type now exposes id(), uuid(), killId(), and doneId(), which are
explicit keys used in the RedisBroker implementation.

heroku/busl,heroku/busl,cyx/busl