code: private void readTrailer(final GZIPArchive.ReadEntry entry) throws IOException {
  
  		// CRC32
  
  		entry.crc32 = readLEInt(input);
  		if (LOGGER.isTraceEnabled()) LOGGER.trace("CRC read from stream {}", Integer.valueOf(entry.crc32));
  
  		// ISIZE
  
  		final int iSize = readLEInt(input);
  		if (entry.uncompressedSkipLength != iSize) throw new GZIPArchive.FormatException("Length mismatch between (warc) extra gzip fields uncompressed-skip-length (" + entry.uncompressedSkipLength + ") and ISIZE (" + iSize + ")");
  
  	}
docs: Reads the GZIP entry trailer (populating the entry CRC metadata).
  
  @param entry the entry where to store the CRC of the entry.