code: func Wrap(namespace string, f Factory, options ...FactoryOption) metrics.Factory {
  	factory := &factory{
  		scope:    namespace,
  		factory:  f,
  		scopeSep: ".",
  		tagsSep:  ".",
  		tagKVSep: "_",
  	}
  	for i := range options {
  		options[i](factory)
  	}
  	return factory
  }
docs: // Wrap is used to create an adapter from xkit.Factory to metrics.Factory.