@Override
public void onDone(Key k) {
Pair<Repository, String> pair = tracker.get(k);
callback.buildEnded(pair.getT(), pair.getU(), Status.UNKNOWN);
}
@Override
public void onStart(Key k) {
Pair<Repository, String> pair = tracker.get(k);
callback.buildStarted(pair.getT(), pair.getU());
}