@Override
                public String toString() {
                    int length = (count > 0 && buf[count - 1] == CR) ? count - 1 : count;
                    try {
                        return new String(buf, 0, length, charset.name());
                    } catch (UnsupportedEncodingException e) {
                        throw new AssertionError(e); // Since we control the charset this will never happen.
                    }
                }
Reads the next line. A line ends with {@code "\n"} or {@code "\r\n"},
this end of line marker is not included in the result.

@return the next line from the input.
@throws IOException  for underlying {@code InputStream} errors.
@throws EOFException for the end of source stream.
VideoSqlLite/src/main/java/com/yc/videosqllite/disk/StrictLineReader.java