Fix crashes related to Realm threading

ios/App/Shared/player/ActivePlaybackSession.swift

@@ -0,0 +1,41 @@
+//
+//  ActivePlaybackSession.swift
+//  App
+//
+//  Created by Ron Heft on 8/16/22.
+//
+
+import Foundation
+import RealmSwift
+
+class ActivePlaybackSession {
+    
+    static let shared = ActivePlaybackSession()
+    
+    private let queue = DispatchQueue(label: "ABSActivePlaybackSession")
+    private var _session: PlaybackSession?
+    
+    private init() {
+        // Singleton
+    }
+    
+    func startSession(_ session: ThreadSafeReference<PlaybackSession>) {
+        queue.sync {
+            _session = try? Realm().resolve(session)
+        }
+    }
+    
+    // This is a funky method, but it ensures the accessing thread gets a live reference to session properly resolved
+    func get() -> PlaybackSession? {
+        var activeSession: ThreadSafeReference<PlaybackSession>?
+        queue.sync {
+            let realm = try! Realm()
+            guard let session = _session else { return }
+            r
+            activeSession = ThreadSafeReference(to: session)
+        }
+        guard let activeSession = activeSession else { return nil }
+        return try? Realm().resolve(activeSession)
+    }
+    
+}