Add unique_ptr<TaskRunner>

include/ftxui/component/screen_interactive.hpp

@@ -26,6 +26,10 @@ struct Event;
 using Component = std::shared_ptr<ComponentBase>;
 class ScreenInteractivePrivate;
 
+namespace task {
+  class TaskRunner;
+}
+
 /// @brief ScreenInteractive is a `Screen` that can handle events, run a main
 /// loop, and manage components.
 ///
@@ -40,6 +44,9 @@ class ScreenInteractive : public Screen {
   static ScreenInteractive FitComponent();
   static ScreenInteractive TerminalOutput();
 
+  // Destructor.
+  ~ScreenInteractive();
+
   // Options. Must be called before Loop().
   void TrackMouse(bool enable = true);
 
@@ -156,6 +163,8 @@ class ScreenInteractive : public Screen {
   std::unique_ptr<Selection> selection_;
   std::function<void()> selection_on_change_;
 
+  std::unique_ptr<task::TaskRunner> task_runner_;
+
   friend class Loop;
 
  public: