saveCheckpoint method
Requests a checkpoint snapshot; resolves with the saved reply.
Implementation
Future<CheckpointMessage> saveCheckpoint(String missionId) {
final requestId =
'c-save-$missionId-${DateTime.now().millisecondsSinceEpoch}';
send(
ZapProtocol.encodeLine(
ZapProtocol.envelope(
'checkpoint',
requestId,
DateTime.now().toUtc().toIso8601String(),
{'missionId': missionId, 'kind': 'save'},
),
),
);
return _awaitCheckpoint(missionId, 'saved', requestId: requestId);
}