Custom Notifier
To create a custom notifier you must have a struct that implements the
notifier.Notifier interface.
In parameter you will receive a notifier.DiffCache struct that will tell you what has changed in your flag configuration.
import (
	ffclient "github.com/thomaspoignant/go-feature-flag"
	"github.com/thomaspoignant/go-feature-flag/notifier/notifier"
	"sync"
)
type Notifier struct{}
func (c *Notifier) Notify(diff notifier.DiffCache) error {
	// ...
	// do whatever you want here
}