docs/contributing/timeline-profile.md
Sometimes performance issues are hard to identify and recreate. If you notice a regression and can reproduce it, you can use the Timeline tools in Chrome Dev Tools to take a snapshot of the application performance and attach it to an issue.
Launch Desktop and select View | Toggle Developer Tools.
Get the Desktop application ready to perform the problem action.
Select the Performance tab. Ensure the Disable JavaScript samples option is unchecked.
Press the Record button on the left to start recording.
Perform the problem action in Desktop. Try and keep the test focused on the issue you're seeing.
Switch back to the Developer tools and press Stop to complete recording.
In the header, click the Save profile... menu item. Save the JSON file somewhere you can access later.
Compress the JSON file to reduce the file size (it could be 10MB or more depending on how long you ran the test for).
Attach the file to your GitHub issue so the contributors can load this into their environment and spelunk the diagnostic information.