protected static InputStream countingStream(InputStream in, int lookback) throws IOException {
        CountingInputStream cin = new CountingInputStream(in);
        cin.mark(lookback); 
        return cin;
    }
protected static InputStream countingStream ( InputStream in , int lookback ) throws IOException { CountingInputStream cin = new CountingInputStream ( in ) ; cin . mark ( lookback ) ; return cin ; }
A CountingInputStream is inserted to read compressed-offsets.

@param in stream to wrap
@param lookback tolerance of initial mark
@return original stream wrapped in CountingInputStream
@throws IOException