docs: @Nullable
    protected byte [] getBoundary (@Nonnull final String sContentType)
    {
      // Parameter parser can handle null input
      final ICommonsMap <String, String> aParams = new ParameterParser ().setLowerCaseNames (true)
                                                                         .parse (sContentType, new char [] { ';', ',' });
      final String sBoundaryStr = aParams.get ("boundary");
      if (sBoundaryStr == null)
        return null;
      return sBoundaryStr.getBytes (StandardCharsets.ISO_8859_1);
    }