Statuses

A generation moves forward only: queued, then running, then succeeded or failed.

Status	Meaning
`queued`	Accepted and waiting. Your input files are fetched and checked at this stage.
`running`	A route is working on it.
`succeeded`	Done. `outputs` has the files and the price is charged, once.
`failed`	Stopped. `error` says why. Nothing is charged and the reservation is released.

succeeded and failed are final. A generation that is still running after 6 hours fails with timeout.
A failed generation is free. To try again, submit a new one with a new Idempotency-Key.
There is no cancel: a started generation runs to the end, and you are charged only if it succeeds.
There are no webhooks for generations: poll. (The Formats API can call a webhook_url for a run.)