code: func (r *Router) Match(f func(*http.Request) bool, h Handler) {
  	matcher := func(r *http.Request, rm *mux.RouteMatch) bool {
  		return f(r)
  	}
  
  	r.mux.MatcherFunc(matcher).Handler(r.handler(h))
  }
docs: // Match adds a route that will be matched if f returns true.