lib/sync-server.js
function stop(dataset_id, cb) {
  if (!syncStarted) {
    return cb();
  }
  debug('[%s] stop sync for dataset', dataset_id);
  syncStorage.updateManyDatasetClients({datasetId: dataset_id}, {stopped: true}, cb);
}
function stop(dataset_id, cb) {
  if (!syncStarted) {
    return cb();
  }
  debug('[%s] stop sync for dataset', dataset_id);
  syncStorage.updateManyDatasetClients({datasetId: dataset_id}, {stopped: true}, cb);
}
Stop cloud data sync for the specified dataset_id