SUBMIT_MESSAGE
POST /v1/messages: envelope submission, ServerAuth-signed by the sending device since S1 (docs/server-authentication.md). An absolute path, not device-scoped: the device is the signed request's address.
POST /v1/messages: envelope submission, ServerAuth-signed by the sending device since S1 (docs/server-authentication.md). An absolute path, not device-scoped: the device is the signed request's address.