Video optimizations (#18)

* use events for `VideoTrackRenderer`

* logger

* implemented visibility detection

* optimize code with 1 param debounce func

* stop pending visibility event when disposed

* clean up

* mark internal

* report to track

* call dispose on pub and track

* use internal events to receive visibility events

* clean up visibility for disposed track

* listen to track visibility events on pub

* re-design

* quickly re-enable

* clean up

* clean up

lib/src/utils.dart

@@ -138,18 +138,18 @@ class Utils {
     ];
   }
 
-  // makes a debounce func
-  static Function createDebounceFunc(
-    Function f, {
+  // makes a debounce func, with 1 param
+  static Function(T) createDebounceFunc<T>(
+    Function(T) f, {
     Function(Function)? cancelFunc,
     required Duration wait,
   }) {
     Timer? t;
-    return () {
+    return (p) {
       t?.cancel();
       t = Timer(wait, () {
         t = null;
-        f();
+        f(p);
       });
       // pass back the cancel method so we can cancel it when no longer needed
       cancelFunc?.call(t!.cancel);