Create a sandbox template

Makes a retried create safe. Choose one value per create you mean to make, 1 to 512 bytes (bytes, not characters), such as a UUID, and send it again on every retry of that create. The first request with a key runs, and a 2xx answer is kept for 24 hours: a repeat with the same key and the same body gets that answer back, with the same status and the header Idempotent-Replayed: true, and creates nothing. A batch create compares the body byte for byte; a VM or pod create compares the fields it decodes, so whitespace and key order do not count. A repeat while the first request is still running answers 409; repeat it a second later. The same key with a different body answers 422. An answer other than a 2xx is not kept, so a retry after a 4xx or a 5xx runs again. A 2xx too large to keep holds the key without it: every repeat answers 409 and creates nothing. Keys are scoped to the organization and the operation.