private void persist(@NotNull Url repoUrl, @NotNull BranchCopyData data) {
    // todo - rewrite of rather big piece; consider rewriting
    synchronized (myPersistenceLock) {
      TreeMap<String, BranchCopyData> map = myPersistentMap.get(repoUrl);
      if (map == null) {
        map = new TreeMap<>();
      }
      map.put(data.getTarget().toString(), data);
      myPersistentMap.put(repoUrl, map);
      myPersistentMap.force();
    }
  }
private void persist(@NotNull Url repoUrl, @NotNull BranchCopyData data)