code: func (r *Route) GetMethods() ([]string, error) {
  	if r.err != nil {
  		return nil, r.err
  	}
  	for _, m := range r.matchers {
  		if methods, ok := m.(methodMatcher); ok {
  			return []string(methods), nil
  		}
  	}
  	return nil, errors.New("mux: route doesn't have methods")
  }
docs: // GetMethods returns the methods the route matches against
  // This is useful for building simple REST API documentation and for instrumentation
  // against third-party services.
  // An error will be returned if route does not have methods.