tree.go
func RegisterMethod(method string) {
	if method == "" {
		return
	}
	method = strings.ToUpper(method)
	if _, ok := methodMap[method]; ok {
		return
	}
	n := len(methodMap)
	if n > strconv.IntSize {
		panic(fmt.Sprintf("chi: max number of methods reached (%d)", strconv.IntSize))
	}
	mt := methodTyp(math.Exp2(float64(n)))
	methodMap[method] = mt
	mALL |= mt
}
func RegisterMethod(method string) {
	if method == "" {
		return
	}
	method = strings.ToUpper(method)
	if _, ok := methodMap[method]; ok {
		return
	}
	n := len(methodMap)
	if n > strconv.IntSize {
		panic(fmt.Sprintf("chi: max number of methods reached (%d)", strconv.IntSize))
	}
	mt := methodTyp(math.Exp2(float64(n)))
	methodMap[method] = mt
	mALL |= mt
}
// RegisterMethod adds support for custom HTTP method handlers, available
// via Router#Method and Router#MethodFunc