added Do method for raw query by single conn from pool.Conn()

[Oleglacto]

No description provided.

[Oleglacto]

Hello! I want to call Do method when I got Conn from redis.Pool. This PR can help me do this

[Oleglacto]

@vmihailenco can u make review please?

[ndyakov]

@Oleglacto can you please describe your usecase and add tests?

[Oleglacto]

@ndyakov It is necessary to execute a raw query on a connection from the pool. Currently, this capability is not available, and workarounds such as Get, Set, etc., have to be used.

[ndyakov]

@Oleglacto on top of my head i cannot think why this should not be possible. Any ideas? How will this behave if you are working with a connection that is in a pub/sub state?

p.s. Also the test that is added is failing cc @Oleglacto

[Oleglacto]

@ndyakov Thanks for waiting. Type Conn from redis.go doesn't support pub/sub. I added this method for cmdble interface and it should work fine

I will trying to fix my test.

upd. fixed

[ndyakov]

@Oleglacto any specific reason why this is not in commands.go ? I don't see the need to add additional file for it.

[Oleglacto]

I created a new file because I didn't know where to add the changes.

I'll move it now