What does this mean ?
I had this in the beginning and it stopped when I fully downloaded the game.
As Cookiefamous said above, "resource stalls" most commonly refers to the game streaming missing data or loading data assets from your hard drive. It should almost stop happening entirely if you wait for the game to finish the download. Though that said, you can just ignore it if you're not having any issues.
I found more about it here:
One final question tho is there a way to be sure i have downloaded everything ? As i said i waited for the launcher to say 100% before it hit play. But when i play campaign i still see streaming data (again no issue here, just curios)
The link that Nidhoggr provided is a sticky topic on the US server. Why does a Sticky like that not exists here ? This would prevent confusion and people making topic like these. I hope you will make such a topic or sticky this topic for future players that stumble on this