var Resource … type Feature … func newFeature[T any](suffix string, parse func(string) (T, bool)) Feature[T] { … } // Key returns the environment variable key that needs to be set to enable the // feature. func (f Feature[T]) Key() string { … } // Lookup returns the user configured value for the feature and true if the // user has enabled the feature. Otherwise, if the feature is not enabled, a // zero-value and false are returned. func (f Feature[T]) Lookup() (v T, ok bool) { … } // Enabled returns if the feature is enabled. func (f Feature[T]) Enabled() bool { … }