Add throttling of usercount frames

src/util/throttle.js

@@ -0,0 +1,9 @@
+import lo from 'lodash';
+
+export function throttle(fn, timeout) {
+    return lo.debounce(fn, timeout, {
+        leading: true,
+        trailing: true,
+        maxWait: timeout
+    });
+}