Add frame timings

[pierd]

Addresses #1121

Makes input to rendered available in the debugger.

[ten3roberts]

Left some comments and questions 😊

[philpax]

LGTM outside of what Freja mentioned.

We might want to get timings for individual systems at some point int he future, but there's no particular rush. The breakdown you've done so far should be enough to get some useful information! Nice work :)

[philpax]

Shall we merge this?

[pierd]

Shall we merge this?

I'm going to update the structure a bit to make packages less coupled but that'll be after the Xmas break.

As for the coupling itself.. there'll still be coupling around the reporting api (whatever the report method would it be other parts have to know how (currently report_event on ambient_timings::Reporter) and what to report (currently TimingEvent/TimingEventType)). Using &'static str just makes the coupling implicit instead of explicit.

[ten3roberts]

Looks great,

I suppose we could say it is a good timing to merge this 😛