public static MultipleLogWriter GeyInstance()
 {
     if (_multipleLogWriter == null)
     {
         _multipleLogWriter = new MultipleLogWriter();
     }
     return(_multipleLogWriter);
 }
        static void Main(string[] args)
        {
            ILogWriter consoleWriter = new ConsoleLogWriter();

            consoleWriter.LogError("Записываем...");

            var fileWriter = new FileLogWriter(@"D:\Git\Lessons\nordic-it-netcore\13\HomeWork\log.txt");

            fileWriter.WriteMessage("Записываем..", MessageType.Error);

            var multipleWriter = new MultipleLogWriter(new ILogWriter[2] {
                fileWriter, consoleWriter
            });

            multipleWriter.LogError(" \"Ошибка\" ");
            multipleWriter.LogInfo(" \"Информация\" ");
            multipleWriter.LogWarning("\"Предупреждение\" ");
        }