Requests made before opening Network panel are not registered

[elliette]

Steps to reproduce:

1. Trigger some network requests
2. Open the network panel

Expected: requests should be visible in the network panel Actual: requests are not visible in the network panel

FYI @srawlins

[elliette]

Note: Performing a hard refresh on DevTools then causes the missed requests to appear

[srawlins]

I think this is also by design... the network panel is not recording when you start. We could change the behavior, I think, to start recording when DevTools starts... but I think there might be a cost to that? To always be logging (and permanently storing) network request data, even if you never visit the network tab. @bkonyi

[srawlins]

Sort of a duplicate of https://github.com/flutter/devtools/issues/6804

[bkonyi]

From my comment on #9489:

We definitely don't want to start recording network traffic without some indication that the user wants network profiling enabled (e.g., opening the network screen) since I don't believe we actually have a limit to the buffer on the dart:io side, which would result in unbounded memory usage if the application is making a lot of network requests, particularly if they're sending large request/response bodies.