Simple FactoryMethod design pattern real-world example

LogMessage.cs

public class LogMessage
{
    public LogType LogType { get; }
    public string Message { get; }
    public string Source { get; }
    public DateTime Timestamp { get; }
    public Exception Exception { get; }

    private LogMessage(LogType logType, string message, string sourceName, Exception exception = null)
    {
        LogType = logType;
        Message = message;
        Source = sourceName;
        Timestamp = DateTime.Now;
        Exception = exception;
    }

    private LogMessage(LogType logType, string message) : this(logType, message, string.Empty) { }

    public static LogMessage CreateSimple(LogType logType, string message)
        => new LogMessage(logType, message);

    public static LogMessage CreateSimple(LogType logType, string message, string sourceName)
        => new LogMessage(logType, message, sourceName);

    public static LogMessage CreateError(string message, Exception exception)
        => new LogMessage(LogType.Error, message, exception.Source, exception);

    public override string ToString()
    {
        if (Exception != null && !string.IsNullOrEmpty(Source))
            return $"[{Timestamp:T}][{LogType}] {Exception.GetType().Name} thrown from {Source}";

        return string.IsNullOrEmpty(Source)
            ? $"[{Timestamp:T}][{LogType}] {Message}"
            : $"[{Timestamp:T}][{LogType}] <{Source}> {Message}";
    }
}