title: AFNetworking 3.0 multipart request
body: <pre><code>AFHTTPSessionManager *manager = [AFHTTPSessionManager manager];
      manager.requestSerializer = [AFJSONRequestSerializer serializer];
      manager.responseSerializer = [AFJSONResponseSerializer serializer];
      [manager.requestSerializer setValue:[NSString stringWithFormat:@"Bearer %@", [[NSUserDefaults standardUserDefaults] objectForKey:TOKEN]] forHTTPHeaderField:@"Authorization"];
      [manager.requestSerializer setValue:@"application/json" forHTTPHeaderField:@"Accept"];
      [manager.requestSerializer setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
      [manager POST:@"http:xxxxx" parameters:parameters constructingBodyWithBlock:^(id&lt;AFMultipartFormData&gt; formData) {
          [formData appendPartWithFileData:profileImage name:@"file" fileName:@"profileImage.jpg" mimeType:@"image/jpeg"];
      } success:^(NSURLSessionTask *task, id responseObject) {
          completionHandler(responseObject);
      } failure:^(NSURLSessionTask *operation, NSError *error) {
          NSData *errorData = error.userInfo[AFNetworkingOperationFailingURLResponseDataErrorKey];
          NSDictionary *serializedData = [NSJSONSerialization JSONObjectWithData: errorData options:kNilOptions error:nil];
          errorHandler(serializedData);
      }];
  </code></pre>
  
  <p>This method is working fine, but <code>constructingBodyWithBlock</code> is deprecated. How can I optimize code to conform <strong>AFNetworking 3.0</strong> standards?</p>