@MacGyver:I don't believe that out of the box there is support for writing to a file. I'd look at using one of the many logging frameworks which can be plugged into the logging (I love serilog) to provide that
@Jon:If you're super old, like me, @Jon then you might remember that Microsoft tried recreating Java once before in the form of the Microsoft JVM. It did not end well. Indeed you could use System.Diagnostics.TraceSouce but keep in mind that it is kind of windows specific especially the System.Diagnostics.EventLogTraceListener. One of the core goals of Core is to remove these platform dependencies and while we're at it why to fix whatever design problems have crept up over the years in existing code? If you're really set on using TraceSource then perhaps https://github.com/aspnet/Logging/blob/dev/src/Microsoft.Extensions.Logging.TraceSource/TraceSourceLoggerProvider.cs will be of interest to you that allows writing from the new logging into a trace source.