add note

examples/demo_live.html

@@ -14,7 +14,7 @@
   <script type="text/javascript">
     const startTime = 1590590148;
     const arrayLength = 100;
-    this.isZoomed = false;
+    this.isZoomed = false; // TODO: temporary hack to have zoomin|zoomout with `appendData`. It will be moved to Pod.
     const data1 = Array.from({ length: arrayLength }, (el, idx) => [startTime + idx * 10000, Math.floor(Math.random() * 40)]);
     const data2 = Array.from({ length: arrayLength }, (el, idx) => [startTime + idx * 10000, Math.floor(Math.random() * 100)]);
     const data3 = Array.from({ length: arrayLength }, (el, idx) => [startTime + idx * 10000, Math.floor(Math.random() * 20) + 90]);