code: func RequestHandler(name string) func(next xhandler.HandlerC) xhandler.HandlerC {
  	return func(next xhandler.HandlerC) xhandler.HandlerC {
  		return xhandler.HandlerFuncC(func(ctx context.Context, w http.ResponseWriter, r *http.Request) {
  			FromContext(ctx).SetField(name, r.Method+" "+r.URL.String())
  			next.ServeHTTPC(ctx, w, r)
  		})
  	}
  }
docs: // RequestHandler returns a handler setting the request's method and URL as a field
  // to the current context's logger using the passed name as field name.