code: func (r *PrefixedRegistry) Each(fn func(string, interface{})) {
  	wrappedFn := func(prefix string) func(string, interface{}) {
  		return func(name string, iface interface{}) {
  			if strings.HasPrefix(name, prefix) {
  				fn(name, iface)
  			} else {
  				return
  			}
  		}
  	}
  
  	baseRegistry, prefix := findPrefix(r, "")
  	baseRegistry.Each(wrappedFn(prefix))
  }
docs: // Call the given function for each registered metric.