func (r *MapErrorRegistry) MustAddHandler(code int, handler func(body []byte) error) {
	if err := r.AddHandler(code, handler); err != nil {
		panic(err)
	}
}
func (r *MapErrorRegistry) MustAddHandler(code int, handler func(body []byte) error) {
	if err := r.AddHandler(code, handler); err != nil {
		panic(err)
	}
}
// MustAddHandler calls AddHandler and panics in case of an error.