Fix saving as .puffin file

[emilk]

• Fixes Saving as .puffin _sometimes_ breaks #248 ?
• Probably broke in Stream scope information only once #169

[gwen-lg]

I spoke too soon.

[gwen-lg]

I have tested with commit 15e131c (which contain change from #169) and main (with revert update to egui v0.31 who failed to build for me).

And saving a capture in .puffin file seems to work for me.
@emilk : What problem did you encounter?

[emilk]

The scope info (names etc) wasn't being saved to the .puffin file, so a fresh puffin_viewer would show no scopes.

This silent error will be less silent with #245

[gwen-lg]

I don't have this problem.
And I don't understand why you have this problem.
In FrameData.write_into, if scope_collection parameter is None scope info are written from self.scope_delta.
Unless in your case, unlike in my case, scope_delta is cleared ?

[emilk]

My repro: connect puffin_viewer to a server with --url 127.0.0.1:8585, hit save, then try to load the saved .rrd .puffin in a new puffin_viewer process.

Didn't work before this PR, but works with this PR.

[gwen-lg]

.rrd ?
I use Save as entry in puffin_viewer, and it save a .puffin file.
And after close and restart puffin_viewer, when I open the previously saved file, I have all the scope information.
For test, I used a very simple app, with very few scope, I will tests with more complicated profiling.

[emilk]

Sorry, I meant .puffin.

I tried my repro again, and now it works on main O.o. This is very weird.

Before I ended up with this broken file:
broken.puffin.zip

Maybe something else is wrong.

To be honest, #169 added so much complexity that I am considering reverting it

• For instance: Wrong scope descriptions in puffin viewer when running profiled program multiple times #200

[gwen-lg]

Reducing bandwidth ans cpu use by send Stream scope information only once seems to be a good idea, but I haven't look how it is implemented.
I have planned to take a look at your file broken.puffin to investigate. And I can take a look at the code of Streaming scope info only once, and see if I see something or see possible complexity reduction.
If possible wait before revert it.