Implement Smart client handoffs

[cescoffier]

Describe the feature

See https://redis.io/docs/latest/develop/clients/lettuce/connect/#connect-using-smart-client-handoffs-sch.

Contribution

No response

[Ladicek]

Do you know if there's some, you know, actual documentation? What you link to and the pages accessible from there don't explain anything except "here's how you configure your client to enable this".

[cescoffier]

Absolutely not, I just know that lettuce implemented it.