AWS S3 Transfer Utility Multipart delay in resuming uploads (iOS Swift)

Question

Whenever i start uploading files with multipart upload using transfer utility and if the file size is larger like 100mb once i kill the app and launch the app again it gives a delay in resuming the task, But the transfer utility uploadData function does not gives this delay it resumes the upload quickly, Anybody seems to know what's the issue

What i think is with larger files the multipart assembles the file again and then resume it where we left off, But transfer utility uploadData function doesn't do this

transferUtility?.uploadUsingMultiPart(fileURL: fileUrl, bucket: self.bucketName, key: myFileKey, contentType: contenType, expression: expression, completionHandler: completionHandler).continueWith { (task) -> Any? in
       if let error = task.error {
                print("error is: \(error.localizedDescription)")
            }
       if let task = task.result {
                
       }
    return nil
}


transferUtility?.uploadFile(fileUrl, bucket: self.bucketName, key: fileKey, contentType: "image", expression: expression, completionHandler: completionHandler).continueWith { (task) -> Any? in
        if let error = task.error {
            print("error is: \(error.localizedDescription)")
        }
        return nil
}