Is it any future plan to make http_proxy crates able to proxy a TCP backend like redis?

## Let me know if this kind of feature request or question already made

## What is the problem your feature solves, or the need it fulfills?

so learning pingora is exciting thing to learn and now i have a cases that i need to do a proxy for redis. But Found out that `pingora_proxy` only support http proxy through `proxyHttp`

## Describe the solution you'd like

is it possible to make kind of `proxyTcp` In the future so pingora also can handle request that not Http and doesn't need to provide header etc.

## Describe alternatives you've considered

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## Additional context

in my case i want to proxy 2 redis using custom proxy that built with pingora inspired by how sentinel and envoy works. Thank you!