Extraction of video URL for sharing via UIActivityViewController - ios

Question

I'm working on share videos using UIActivityViewController and have some questions about the URL extraction from PHAsset objects.
I use "requestAVAsset" in "PHImageManager" and cast the AVAsset object to AVURLAsset to access its url property. I've tried the following types of activities:
Copy to Drive - this opens Google Drive app (Success)
Google Drive - a dialog shows up for confirmation (Fail) (no video attached in the dialog)
Gmail - (Fail) (mail can be sent but no video attached)
Add to Notes - this add video to built-in Notes app, a dialog should show up for confirmation (Fail) (app freezes after UIActivityViewController disappears and no dialog shows up)
Facebook/LINE - (Fail) (the progress bar never moves)
My questions:
Does the URL extracted by this method has the access to the real resource file of video?
If yes, am I missing something? Are there bugs in my code (see below)?
Code to share contents (inside an UIViewController):
PHImageManager.default().requestAVAsset(forVideo: videoAsset, options: nil, resultHandler: {
(asset: AVAsset?, audioMix: AVAudioMix?, info: [AnyHashable: Any]?) in
if let urlAsset = asset as? AVURLAsset {
print("Share url=\(urlAsset.url.absoluteURL)")
let shareVC: UIActivityViewController = UIActivityViewController(activityItems: [urlAsset.url.absoluteURL], applicationActivities: nil)
shareVC.completionWithItemsHandler = {
(type: UIActivityType?, completed: Bool, returnedItems: [Any]?, err: Error?) in
print("Share result: completed=\(completed), \(type)")
if err != nil {
print("\(err.debugDescription)")
}
}
DispatchQueue.main.async {
self.present(shareVC, animated: true, completion: nil)
}
}
})
Environment: iPhone 7 plus, iOS 10.1.1
Btw, I also tried another 2 methods for sharing.
Using "writeData" in "PHAssetResourceManager" to output video to a temporary directory and then build URL by the file path.
Using "requestExportSession" in "PHImageManager" to output video to a temporary directory and then build URL by the file path.
These method work fine. In my opinion, this is because the video file can be accessed directly by the extracted url. But they are not suitable for me since I would like to share not only single file but also multiple files within one action. (They take time to process data)