@Override
    public void write(int b) throws IOException {
        filePosition++;
        super.write(b);
    }
@Test
    public void testWriteByte() throws IOException {
        byte[] arr = new byte[257];
        for (int i=0; i<256; i++) {
            arr[i] = (byte)i;
            writer.write(i);
        }
        arr[256] = (byte)0x80;
        writer.write(0x180);

        expectData(arr);
    }