auth0.go
func NewKeyProvider(key interface{}) SecretProvider {
	return SecretProviderFunc(func(_ *http.Request) (interface{}, error) {
		return key, nil
	})
}
func NewKeyProvider(key interface{}) SecretProvider {
	return SecretProviderFunc(func(_ *http.Request) (interface{}, error) {
		return key, nil
	})
}
// NewKeyProvider provide a simple passphrase key provider.