Apply timeout to requestIdleCallback

Since there is a delay in initialization when the first post on the
screen is a video, it forces timeout to be executed within that time.

src/internal/extension-proxy.ts

@@ -2,6 +2,8 @@ import bind from './bind';
 import Extension, { IExtension } from './extension';
 import postElement from './post-element';
 
+const timeout = 2000;
+
 class ExtensionProxy implements IExtension {
   private executionCount: number;
   private extension: Extension;
@@ -15,7 +17,7 @@ class ExtensionProxy implements IExtension {
 
   public activate() {
     if (!this.isActivated) {
-      window.requestIdleCallback(this.handleActivate);
+      window.requestIdleCallback(this.handleActivate, { timeout });
     }
   }
 
@@ -32,7 +34,7 @@ class ExtensionProxy implements IExtension {
       this.isActivated = true;
       this.extension.activate();
     } else {
-      window.requestIdleCallback(this.handleActivate);
+      window.requestIdleCallback(this.handleActivate, { timeout });
     }
   }