The Iceberg REST spec defines Idempotency-Key as a UUID format,
with the example payloads showing UUIDv7 (timestamp-prefixed). UUIDv7
is preferred because keys are roughly time-orderable, which makes
server-side dedup windows simpler to reason about.
Generate an RFC 9562 UUIDv7 string.
The Iceberg REST spec defines
Idempotency-Keyas a UUID format, with the example payloads showing UUIDv7 (timestamp-prefixed). UUIDv7 is preferred because keys are roughly time-orderable, which makes server-side dedup windows simpler to reason about.Layout (RFC 9562 ยง5.7): 48-bit unix-ms timestamp | 4-bit version (0111) | 12-bit rand_a 2-bit variant (10) | 62-bit rand_b