code: @Nonnull
    public MimeType addParameter (@Nonnull @Nonempty final String sAttribute, @Nonnull @Nonempty final String sValue)
    {
      return addParameter (new MimeTypeParameter (sAttribute, sValue));
    }
docs: Add a parameter.
  
  @param sAttribute
  Parameter name. Must neither be <code>null</code> nor empty and must
  match {@link MimeTypeParser#isToken(String)}.
  @param sValue
  The value to use. May neither be <code>null</code> nor empty. Must
  not be a valid MIME token.
  @return this