title: k6 - storing data between setup and default functions
body: <p>I want to store an id in a setup section, what I got when I upload a file for an endpoint, and after that, I need to get back the uploaded element in the default section multiple times.
  I tried to use a helper function with a setter and getter but it gave back undefined in the default function.
  Is there any easy way to store a number between the setup function and the default?</p>