Custom ITraceWriter

public class NLogTraceWriter : ITraceWriter
{
    private static readonly Logger Logger = LogManager.GetLogger("NLogTraceWriter");

    public TraceLevel LevelFilter
    {
        // trace all messages. nlog can handle filtering
        get { return TraceLevel.Verbose; }
    }

    public void Trace(TraceLevel level, string message, Exception ex)
    {
        LogEventInfo logEvent = new LogEventInfo
        {
            Message = message,
            Level = GetLogLevel(level),
            Exception = ex
        };

        // log Json.NET message to NLog
        Logger.Log(logEvent);
    }

    private LogLevel GetLogLevel(TraceLevel level)
    {
        switch (level)
        {
            case TraceLevel.Error:
                return LogLevel.Error;
            case TraceLevel.Warning:
                return LogLevel.Warn;
            case TraceLevel.Info:
                return LogLevel.Info;
            case TraceLevel.Off:
                return LogLevel.Off;
            default:
                return LogLevel.Trace;
        }
    }
}

IList<string> countries = new List<string>
{
    "New Zealand",
    "Australia",
    "Denmark",
    "China"
};

string json = JsonConvert.SerializeObject(countries, Formatting.Indented, new JsonSerializerSettings
{
    TraceWriter = new NLogTraceWriter()
});

Console.WriteLine(json);
// [
//   "New Zealand",
//   "Australia",
//   "Denmark",
//   "China"
// ]