swift

 Auth0
        .authentication().createUser(email: email,
                                     username: username,
                password: "hellogrow",
                connection: "Username-Password-Authentication",
                userMetadata: [:]).start { result in
            switch result {
            case .success( _):
                UserAuthenticationManager.sharedInstance.username = username
                UserAuthenticationManager.sharedInstance.email = email
                self.loginUser(email: email, onSuccess: onSuccess, onFailure: onFailure)
                break
            case .failure(let error):
                self.handleError(error: error, onFailure: onFailure)
                break
            }
        }