Monorail is spec'ed to allow up to 300 requests per minute within a 5 minute window per client.

While this is ok for now, as the number of FlakeIssues that need updating increase this will result in Monorail denying the requests resulting in http 4xx errors.

Per discussion with jrobbins@ we should throttle the requests, and use exponential backoff should we hit the limit and see the errors

As of now we are nowhere near the 1500 limit but depending on the rate that bugs for flakes are logged, flakes are detected, and the rate they're fixed this could grow.