saveHubIdentity function
Saves identity's seeds to path (the host's rotation/rebind path).
Implementation
Future<void> saveHubIdentity(String path, HubIdentity identity) async {
final signingSeed = await identity.signingKeyPair.extractPrivateKeyBytes();
final dhPriv = await identity.dhKeyPair.extractPrivateKeyBytes();
await File(path).parent.create(recursive: true);
await File(path).writeAsString(
'ed25519:${base64Encode(signingSeed)}\n'
'x25519:${base64Encode(dhPriv)}\n',
flush: true,
);
await _chmod600(path);
}