anchor.diff:    }
   
     /// Issue an authorization token to a user after authenticating them via [username] and [password].
  -  Future<AuthorizationTokenResponse> resourceOwnerPasswordCredentialsGrant(
  +  FutureOr<AuthorizationTokenResponse> resourceOwnerPasswordCredentialsGrant(
         Client client,
         String username,
         String password,
  
positive.code:   }
  
    /// Performs a client credentials grant. Only use this in situations where the client is 100% trusted.
    Future<AuthorizationTokenResponse> clientCredentialsGrant(
        Client client, RequestContext req, ResponseContext res) async {
      var body = await req.parseBody().then((_) => req.bodyAsMap);
      throw new AuthorizationException(
        new ErrorResponse(
          ErrorResponse.unsupportedResponseType,
          'Client credentials grants are not supported.',
          body['state']?.toString() ?? '',
        ),
        statusCode: 400,
  
negative.code:   ///
    /// Note that in cases where this is called, there is no guarantee
    /// that the user agent has not been compromised.
    FutureOr<AuthorizationTokenResponse> implicitGrant(
        Client client,
        String redirectUri,
        Iterable<String> scopes,
  