code: protected final long parseVersionAndFlags(ByteBuffer content) {
          version = IsoTypeReader.readUInt8(content);
          flags = IsoTypeReader.readUInt24(content);
          return 4;
      }
docs: Parses the version/flags header and returns the remaining box size.
  
  @param content the <code>ByteBuffer</code> that contains the version &amp; flag
  @return number of bytes read