/// <summary>
        /// Grants the resource owner credentials.
        /// </summary>
        /// <param name="context">The context.</param>
        /// <returns></returns>
        public override Task GrantResourceOwnerCredentials(OAuthGrantResourceOwnerCredentialsContext context)
        {
            //TODO: do password validation here...
            throw new NotImplementedException();
#if false
            if (context.Password != "password")
            {
                context.SetInvalidGrantErrorAndReject();
                return;
            }

            // Create or retrieve a ClaimsIdentity to represent the
            // Authenticated user:
            var identity = new ClaimsIdentity(context.Options.AuthenticationType);
            identity.AddClaim(new Claim("user_name", context.UserName));
            identity.AddClaim(new Claim(ClaimTypes.Role, "Admin"));

            // Identity info will ultimately be encoded into an Access Token
            // as a result of this call:
            await Task.FromResult(context.Validated(identity));
#endif // false
        }