Added observable & observer for TTS, to react faster to new messages when waiting.

Chat/Observers/TTSConsumer.cs

@@ -0,0 +1,41 @@
+using Serilog;
+using TwitchChatTTS.Chat.Speech;
+
+namespace TwitchChatTTS.Chat.Observers
+{
+    public class TTSConsumer : IObserver<TTSGroupedMessage>
+    {
+        private readonly TTSEngine _engine;
+        private readonly ILogger _logger;
+
+        private IDisposable? _cancellation;
+
+        public TTSConsumer(TTSEngine engine, ILogger logger)
+        {
+            _engine = engine;
+            _logger = logger;
+        }
+
+        public virtual void Subscribe(TTSPublisher provider) =>
+            _cancellation = provider.Subscribe(this);
+
+        public virtual void Unsubscribe()
+        {
+            _cancellation?.Dispose();
+        }
+
+        public void OnCompleted()
+        {
+        }
+
+        public void OnError(Exception error)
+        {
+            _logger.Error(error, "An error happened while observing for TTS messages.");
+        }
+
+        public void OnNext(TTSGroupedMessage value)
+        {
+            _engine.PlayerSource?.Cancel();
+        }
+    }
+}