mux.go
func (mx *Mux) MethodFunc(method, pattern string, handlerFn http.HandlerFunc) {
	mx.Method(method, pattern, handlerFn)
}
func (mx *Mux) MethodFunc(method, pattern string, handlerFn http.HandlerFunc) {
	mx.Method(method, pattern, handlerFn)
}
// MethodFunc adds the route `pattern` that matches `method` http method to
// execute the `handlerFn` http.HandlerFunc.