Using arrow functions changes `this` context, which is undesired in tests, e.g. it makes it impossible to setup things like pretender (`this.server`) in `beforeEach` hooks.
Ember guides always use classic functions in examples (e.g. https://guides.emberjs.com/release/testing/test-types/), and that's what it uses in its own test suite, as do various addons and ember apps.
It was also already used in Discourse where `this` was required. Moving forward, it will be needed in more places as we migrate toward ember-cli.
(I might later add a custom rule to eslint-discourse-ember to enforce this)
* FEATURE: when we fail to ship topic timings attempt to retry
This change amends it so
1. Topic timings are treated as background requests and subject to more
aggressive rate limits.
2. If we notice an error when we ship timings we back off exponentially
The commit allows 405, 429, 500, 501, 502, 503 and 504 errors to be retried.
500+ errors usually happen when self hosters are rebuilding or some other
weird condition.
405 happens when site is in readonly.
429 happens when user is rate limited.
The retry cadence is hardcoded in AJAX_FAILURE_DELAYS, longest delay is
40 seconds, we may consider enlarging it.
After the last delay passes we give up and do not write timings to the
server.
* Address feedback
- Omit promise, no need to use promises in sendNextConsolidatedTiming
- Correct issue where >= -1 was used and > -1 was intended
- Use objects for consolidated timings instead of Array
- Stop using shift/unshift and instead use push / pop which are faster
* Move consolidated timing initialization to constructor
* Remove TODO and just console.warn if we have an issue
