code: public static long getCRC(byte[] buffer) {
          CRC32 crc = new CRC32();
          crc.update(buffer);
          return crc.getValue();
      }
docs: Compute CRC32 value for byte[]
  
  @param buffer all the bytes in the buffer will be used for CRC32 calculation
  
  @return a CRC32 value for the given byte array