scheme.go
func Unregister(name string) *Scheme {
	scheme, ok := schemeMap[name]
	if ok {
		for _, alias := range scheme.Aliases {
			delete(schemeMap, alias)
		}
		delete(schemeMap, name)
		return scheme
	}
	return nil
}
func Unregister(name string) *Scheme {
	scheme, ok := schemeMap[name]
	if ok {
		for _, alias := range scheme.Aliases {
			delete(schemeMap, alias)
		}
		delete(schemeMap, name)
		return scheme
	}
	return nil
}
// Unregister unregisters a Scheme and all associated aliases.