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}.
VideoSqlLite/src/main/java/com/yc/videosqllite/disk/StrictLineReader.java