code: private void checkExistingTracks() {
          SwingUtilities.invokeLater(new Runnable() {
              @Override
              public void run() {
                  for (Map.Entry<DeckReference, TrackMetadata> entry : MetadataFinder.getInstance().getLoadedTracks().entrySet()) {
                      if (entry.getKey().hotCue == 0) {  // The track is currently loaded in a main player deck
                          checkIfSignatureReady(entry.getKey().player);
                      }
                  }
              }
          });
      }
docs: Send ourselves "updates" about any tracks that were loaded before we started, since we missed them.