code: func RemoteAddrHandler(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) {
  			if host, _, err := net.SplitHostPort(r.RemoteAddr); err == nil {
  				FromContext(ctx).SetField(name, host)
  			}
  			next.ServeHTTPC(ctx, w, r)
  		})
  	}
  }
docs: // RemoteAddrHandler returns a handler setting the request's remote address as a field
  // to the current context's logger using the passed name as field name.