/// <summary>
 /// Called when a client tries to change its user identity.
 /// </summary>
 private void OnImpersonateUser(object sender, UaImpersonateUserEventArgs args)
 {
     // check for a user name token.
     if (args.NewIdentity is UserNameIdentityToken userNameToken)
     {
         args.Identity = VerifyPassword(userNameToken);
     }
 }
        /// <summary>
        /// Called when a client tries to change its user identity.
        /// </summary>
        private void OnImpersonateUser(object sender, UaImpersonateUserEventArgs args)
        {
            // check for a user name token.
            var userNameToken = args.NewIdentity as UserNameIdentityToken;

            if (userNameToken != null)
            {
                args.Identity = VerifyPassword(userNameToken);
                return;
            }
        }