How do I implement custom logging?

The Catalog app has a complete code example demonstrating custom logging.

This article shows how to implement logging to the Visual Studio output window.

Implement a class derived from ICustomLogger, overriding the various log methods for each log level (Warn, Error, etc.):

class CustomLogger : ICustomLogger
{
    private static void Log(string tag, string message)
    {
        System.Diagnostics.Debug.WriteLine($"{tag}: {message}");
    }

    public void Critical(string tag, string message)
    {
        Log(tag, message);
    }

    public void Error(string tag, string message)
    {
        Log(tag, message);
    }

    public void Warn(string tag, string message)
    {
        Log(tag, message);
    }

    public void Info(string tag, string message)
    {
        Log(tag, message);
    }

    public void Debug(string tag, string message)
    {
        Log(tag, message);
    }

    public void Trace(string tag, string message)
    {
        Log(tag, message);
    }
}

Then, assign an instance of it to the Nutrient Logger:

// Set up your own custom logger.
var customLogger = new CustomLogger();

// Set it in the Nutrient logger.
var logger = Logger.Instance;
logger.CustomLogger = customLogger;

// Choose your own log level. Debug is useful for sending reports to us.
logger.CurrentLevel = Level.Debug;

// You can use the logger for your own logs too.
logger.Info("MYAPP", "Created customer logger and set log level to Debug");

Consider logging your application to a file that users can send to you. This typically saves our customers a lot of time when diagnosing issues.