问如何在asp.net owin api项目中启用JSON.NET序列化/反序列化跟踪？

EN

public class SimpleTracer : ITraceWriter
{
    public void Trace(HttpRequestMessage request, string category, TraceLevel level, 
        Action<TraceRecord> traceAction)
    {
        TraceRecord rec = new TraceRecord(request, category, level);
        traceAction(rec);
        WriteTrace(rec);
    }

     //here you can write logic for json serialization/deserialization    
    protected void WriteTrace(TraceRecord rec)
    {
        var message = string.Format("{0};{1};{2}", 
            rec.Operator, rec.Operation, rec.Message);
        System.Diagnostics.Trace.WriteLine(message, rec.Category);
    }
}

 config.Services.Replace(typeof(ITraceWriter), new SimpleTracer());