How to improve the performance of REST API calls?

Summary

How to improve the performance of REST API calls?

Content

Hi,

We have schema attributes defined for answers in Agent Desktop->Authoring. One such attribute is "Regulations", which is a datalist.

The business requirement is as follows:
We have to display all the Regulation attribute values as a dropdown on Customer portal. For ex: abc, xyz, pqr etc...
User selects one of the Regulation, say - "abc" and clicks on "Download Report" button.
This should download all the articles with Regulations attribute set to "abc" into a csv file.

To achieve the above requirement, we are following the below steps in the code, making more than one API call inside loop: