pref: add throttle to IntersectionObserver

Author: codeacme17

src/utils/lazy-load.ts

@@ -18,6 +18,7 @@ class LazyLoader {
 
       const entry = entries[0]
       const DELAY_TIME = 260
+
       if (entry.intersectionRatio >= 0) {
         this.timer = setTimeout(() => {
           this.handler()