docs: add some extra info for push jobs method use

Author: Kos-M

example/readme.md

@@ -6,3 +6,7 @@ yarn --prod # npm install --only=prod
 cd example
 node index.js
 ```
+
+pushNewJob returns a promise , if you need to throttle some how pushing new tasks in queue , use await , will resolves proportional of the current queue size.
+
+This is usefull for hardware limitations , for big data sets. Otherwise dont await at all , create the promise and leave it.