Support middlewares

[lcd1232]

WHAT

Support middlewares

WHY

see #45

[kochetkov-av]

Nice contribution!

I suggest you add global middleware support. For example for logging or metrics.

To have something like this:

mr.UseMiddleware(LoggingMiddleware(logger))
mr.UseMiddleware(MetricsMiddleware(prometheus_client))

Also, some examples/docs would be nice.

[osamingo]

@lcd1232 Sorry for the code review.

Thanks for suggesting the middleware implementation.
It would be nice if you could do a PR for the middleware implementation only since it is mixed with context operations as well as the middleware implementation.

As @kochetkov-av mentioned, I agree with the way he suggested.
like a chi middleware, https://github.com/go-chi/chi

[lcd1232]

@osamingo I fixed all issues

[kochetkov-av]

My suggestion is to add "after" middleware test if order testing, like this:

res, err := next(c, params)
buf.WriteString(s)
return res, err