Shutdown OkHttp on closing (fixed #235)

Author: devgianlu

core/src/main/java/xyz/gianlu/librespot/core/Session.java

@@ -472,6 +472,9 @@ public void close() throws IOException {
 
         executorService.shutdown();
 
+        client.dispatcher().executorService().shutdownNow();
+        client.connectionPool().evictAll();
+
         if (conn != null) {
             conn.socket.close();
             conn = null;

core/src/main/java/xyz/gianlu/librespot/dealer/DealerClient.java

@@ -366,6 +366,8 @@ public void onMessage(@NotNull WebSocket ws, @NotNull String text) {
 
             @Override
             public void onFailure(@NotNull WebSocket ws, @NotNull Throwable t, @Nullable Response response) {
+                if (closed) return;
+
                 LOGGER.warn("An exception occurred. Reconnecting...", t);
                 ConnectionHolder.this.close();
             }