idempotency-answer-not-kept
Status 409. The type of this problem is the address of this page.
What happened
The first request under this key was carried out, and its answer reached the client that sent it. That answer could not be kept, because it was a stream or a file, because it was larger than the store holds, or because the store failed on the write, so there is nothing to answer a repeat with. Acting on the repeat would do the work a second time.
What to do
Look the result up instead of sending the request again: the first request did what it was asked. The key stays used for http-api.idempotency.ttl seconds. To have every answer replayed, keep the keys in a store that holds the largest answer a route gives, as Where the keys are kept describes.