internal SwitchableContingService(ISettings settings, ICountingAppender appender, ICountingReader reader)
 {
     Ensure.NotNull(settings, "settings");
     Ensure.NotNull(appender, "appender");
     Ensure.NotNull(reader, "reader");
     this.settings = settings;
     this.appender = appender;
     this.reader   = reader;
 }
 internal SwitchableContingService(Settings settings, ICountingAppender appender, ICountingReader reader)
 {
     Ensure.NotNull(settings, "settings");
     Ensure.NotNull(appender, "appender");
     Ensure.NotNull(reader, "reader");
     this.settings = settings;
     this.appender = appender;
     this.reader = reader;
 }