docs: private final byte[] zeroExtend(byte[] dataToPad) {
          assert null != dataToPad;
  
          final int targetLength = 4;
  
          if (targetLength <= dataToPad.length)
              return dataToPad;
  
          byte padded[] = new byte[targetLength];
  
          for (int i = 0; i < dataToPad.length; i++)
              padded[i] = dataToPad[i];
  
          for (int i = dataToPad.length; i < padded.length; i++)
              padded[i] = (byte)0;
  
          return padded;
      }