code: public static void setDefaultFormatter (@Nonnull final BiConsumer <String, BootstrapSystemMessage> aFormatter)
    {
      ValueEnforcer.notNull (aFormatter, "Formatter");
      s_aRWLock.writeLocked ( () -> s_aFormatter = aFormatter);
    }
docs: Set the default text formatter to be used. This can e.g. be used to easily
  visualize Markdown syntax in the system message.
  
  @param aFormatter
  The formatter callback. May not be <code>null</code>.