@Override
  public UUID findFirst(JobAuthorization.State jobState) {
    Query<Key> query =
        Query.newKeyQueryBuilder()
            .setKind(JOB_KIND)
            .setFilter(PropertyFilter.eq(PortabilityJob.AUTHORIZATION_STATE, jobState.name()))
            // .setOrderBy(OrderBy.asc("created"))
            .setLimit(1)
            .build();
    QueryResults<Key> results = datastore.run(query);
    if (!results.hasNext()) {
      return null;
    }
    Key key = results.next();
    return UUID.fromString(key.getName());
  }
Finds the ID of the first {@link PortabilityJob} in state {@code jobState} in Datastore, or
null if none found.

<p>TODO(rtannenbaum): Order by creation time so we can process jobs in a FIFO manner. Trying to
OrderBy.asc("created") currently fails because we don't yet have an index set up.
extensions/cloud/portability-cloud-google/src/main/java/org/datatransferproject/cloud/google/GoogleJobStore.java