private void OnNextConsoleOut(CharactersOut c, IObserver <CharactersOut> observer)
 {
     lock (_copyLock)
     {
         if (Flushing)
         {
             OnNextFlush(c, observer);
         }
         else
         {
             OnNextSource(c, observer);
         }
     }
 }
 private static void OnNextFlush(CharactersOut c, IObserver <CharactersOut> observer) =>
 observer.OnNext(c.Error ? ConsoleOut.ErrorOut(c.Characters) : ConsoleOut.Out(c.Characters));