public void close() throws IOException {
    synchronized (in) {
      if (buf != null) {
        buf = null;
        in.close();
      }
    }
  }
Closes the reader by closing the underlying {@code InputStream} and
marking this reader as closed.

@throws IOException for errors when closing the underlying {@code InputStream}.
core/src/main/java/com/bumptech/glide/disklrucache/StrictLineReader.java