docs: private static Pair<Cluster, Cluster> getTwoLastClusters(@NotNull VirtualFileSystem vfs,
                                                               @NotNull final Transaction txn,
                                                               @NotNull final File file) {
          // todo: seek to end of file without loading all clusters
          try (ClusterIterator iterator = new ClusterIterator(vfs, txn, file)) {
              Cluster prevCluster = null;
              Cluster currCluster = null;
              while (iterator.hasCluster()) {
                  prevCluster = currCluster;
                  currCluster = iterator.getCurrent();
                  iterator.moveToNext();
              }
              return new Pair<>(prevCluster, currCluster);
          }
      }