code: @Nullable
    @OverrideOnDemand
    protected LogMessage createLogMessage (@Nonnull final IErrorLevel eErrorLevel,
                                           @Nonnull final Serializable aMsg,
                                           @Nullable final Throwable t)
    {
      return new LogMessage (eErrorLevel, aMsg, t);
    }
docs: Override this method to create a different LogMessage object or to filter
  certain log messages.
  
  @param eErrorLevel
  Error level. Never <code>null</code>.
  @param aMsg
  The message object. Never <code>null</code>.
  @param t
  An optional exception. May be <code>null</code>.
  @return The returned value. May be <code>null</code> in which case the
  message will not be logged.