Add audio session events

apple/OmnivoreKit/Sources/Services/AudioSession/AudioController.swift

@@ -231,9 +231,16 @@ public class AudioController: NSObject, ObservableObject, AVAudioPlayerDelegate
 
     self.itemAudioProperties = itemAudioProperties
     startAudio()
+
+    EventTracker.track(
+      .audioSessionStart(linkID: itemAudioProperties.itemID)
+    )
   }
 
   public func stop() {
+    let stoppedId = itemAudioProperties?.itemID
+    let stoppedTimeElapsed = timeElapsed
+
     player?.pause()
     timer?.invalidate()
 
@@ -251,6 +258,12 @@ public class AudioController: NSObject, ObservableObject, AVAudioPlayerDelegate
     timeElapsed = 0
     duration = 1
     durations = nil
+
+    if let stoppedId = stoppedId {
+      EventTracker.track(
+        .audioSessionEnd(linkID: stoppedId, timeElapsed: stoppedTimeElapsed ?? 0.0)
+      )
+    }
   }
 
   public func generateVoiceList() -> [(name: String, key: String, selected: Bool)] {

apple/OmnivoreKit/Sources/Utils/EventTracking/TrackableEvents.swift

@@ -4,6 +4,8 @@ public enum TrackableEvent {
   case linkRead(linkID: String, slug: String, originalArticleURL: String)
   case debugMessage(message: String)
   case backgroundFetch(jobStatus: BackgroundFetchJobStatus, itemCount: Int, secondsElapsed: Int)
+  case audioSessionStart(linkID: String)
+  case audioSessionEnd(linkID: String, timeElapsed: Double)
 }
 
 public enum BackgroundFetchJobStatus: String {
@@ -22,6 +24,10 @@ public extension TrackableEvent {
       return "debug_message"
     case .backgroundFetch:
       return "background_fetch"
+    case .audioSessionStart:
+      return "audio_session_start"
+    case .audioSessionEnd:
+      return "audio_session_end"
     }
   }
 
@@ -41,6 +47,15 @@ public extension TrackableEvent {
         "seconds_elapsed": String(secondsElapsed),
         "fetched_item_count": String(itemCount)
       ]
+    case let .audioSessionStart(linkID: linkID):
+      return [
+        "link": linkID
+      ]
+    case let .audioSessionEnd(linkID: linkID, timeElapsed: timeElapsed):
+      return [
+        "link": linkID,
+        "timeElapsed": String(timeElapsed)
+      ]
     }
   }
 }