@Nullable
    //null means no artifacts lasts
  ArrayList<IndexedMavenId> processArtifacts(MavenIndexId mavenIndexId, int startFrom, MavenToken token)
    throws RemoteException, MavenServerIndexerException;
@Nullable
    //null means no artifacts lasts
  ArrayList<IndexedMavenId> processArtifacts(MavenIndexId mavenIndexId, int startFrom, MavenToken token)