AVPlayer with downloaded content doesn't work but streaming content does - swift

Question

I am trying to (1) download a piece of audio from a link, (2) add that newly-downloaded audio to an AVPlayer and (3) play it. Something is going wrong at step (3) and I'm looking for any guidance. Here's the code, including my alamofire and download functions, as I fear something may be going wrong at that stage.
import AVFoundation
class SettingAlarmViewController: UIViewController {
var player:AVPlayer!
override func viewDidLoad() {
super.viewDidLoad()
do {
try AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayback)
}
catch {
// report for an error
}
}
func getLatestPodcastURL(completion: #escaping (URL) -> ()) {
let RSSUrl: String = "https://www.npr.org/rss/podcast.php?id=510318"
Alamofire.request(RSSUrl).responseRSS() {response in
if let podcastURL: String = response.result.value?.items[0].enclosure!
{
let audioURL = URL(string: podcastURL)
completion(audioURL!)
}
else {
//error handling
}
}
}
func downloadSongAsynch(audioUrl: URL, completion: #escaping (URL) -> ()) {
let fileManager = FileManager.default
let documentsDirectoryURL = fileManager.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent("podcasts/")
do {
try fileManager.createDirectory(atPath: documentsDirectoryURL.path,
withIntermediateDirectories: true, attributes: nil)
} catch {
//error handling
}
let destinationUrl = documentsDirectoryURL.appendingPathComponent(audioUrl.lastPathComponent)
URLSession.shared.downloadTask(with: audioUrl, completionHandler: { (location, response, error) -> Void in
guard let location = location, error == nil else { return }
do {
try FileManager.default.moveItem(at: location, to: destinationUrl)
} catch {
//error handling
}
}).resume()
completion(destinationUrl)
}
#IBAction func SetUpBotton(_ sender: Any) {
getLatestPodcastURL() {response in
//Uses an asynchronous call to Alamofire to get the podcast URL
self.downloadPodcastAsynch(audioUrl: response){response2 in
self.player = AVPlayer(url: response2)
print(self.player.currentItem)
}
#IBAction func PlayButton(_ sender: Any) {
player.play()
print(player.currentItem)
}
The log consistently shows my current item: >
But nothing plays. I have checked that the audio is working by trying to use the URL to stream this content. That works fine. I am getting the following:
BoringSSL errors "[BoringSSL] Function boringssl_session_errorlog: line 2871 [boringssl_session_read] SSL_ERROR_ZERO_RETURN(6): operation failed because the connection was cleanly shut down with a close_notify alert
but from what I've read, this is just a bug in the latest update and shouldn't be impacting the download. Any thoughts on this?