code: public FP64 extend(InputStream stream) throws IOException {
      int b;
      while ((b = stream.read()) != -1) {
        extend((byte) b);
      }
      return this;
    }
docs: Extends this fingerprint by the bytes of the stream
  <code>stream</code>, which must be non-null.
  
  @return
  the resulting fingerprint.
  
  @throws IOException
  if an error is encountered reading <code>stream</code>.