fix a race condition in handleScrollEvent (#85)

package.json

@@ -1,7 +1,7 @@
 {
   "name": "tinode-webapp",
   "description": "Tinode messenger for the web",
-  "version": "0.17.9",
+  "version": "0.17.10-rc1",
   "repository": {
     "type": "git",
     "url": "https://github.com/tinode/example-react-js.git"
@@ -68,7 +68,7 @@
     "react": "^17.0.2",
     "react-dom": "^17.0.2",
     "react-intl": "^5.20.2",
-    "tinode-sdk": "^0.17.9"
+    "tinode-sdk": "^0.17.10-rc1"
   },
   "devDependencies": {
     "@babel/core": "^7.14.5",