A connect callback is more flexible than providing connection options using the options API. The user can apply connection specific options (such as socket options) from the connect callback.
Additional small changes:
Don't set command timeout after redisReconnect, because hiredis does this automatically. This saves a few syscalls at reconnect.
Improve documentation of async connect in README. Some of this info seems to have been copied from hiredis, so it wasn't even correct for hiredis-cluster.
A connect callback is more flexible than providing connection options using the options API. The user can apply connection specific options (such as socket options) from the connect callback.
Additional small changes: