id property
ID is the settle-once key: "x402_" + keccak(from|nonce) in hex. It is DERIVED, not minted, so a client that re-submits the same authorization addresses the same settlement and is served again for free rather than charged twice. It is also the id GET /v1/x402/settlements/:id takes.
Please note: This property should have been non-nullable! Since the specification file does not include a default value (using the "default:" property), however, the generated source code must fall back to having a nullable type. Consider adding a "default:" property in the specification file to hide this note.
Implementation
String? id;