Override Client.read_timeout with Request

[TAYTS]

Hi may I check if it is possible to add read_timeout option to Request to override the one in Client?

Wonder if it is not supported by design, didn't find relevant issues/discussions about it from the original feature issue(#2237).

The use case is there could be multiple upstreams and each may have different latency performance and given that we would want to create single Client and re-use instead of create multiple Client and each with different read_timeout config.

I am willing to work on it if this minor change is acceptable