code: public static void registerStats(String path, int blockCount, int freeBlocks,
        int availableBlocks) {
      stats.put(path, new Stats(blockCount, freeBlocks, availableBlocks));
    }
docs: Register stats for a path, which will be used when a matching {@link StatFs} instance is
  created.  A {@link StatFs} instance matches if it extends path. If several registered paths
  match, we pick the longest one.
  
  @param path path to the file
  @param blockCount number of blocks
  @param freeBlocks number of free blocks
  @param availableBlocks number of available blocks