Allow configuring the trace source logger without having to flow a TraceListener instance

[kevinchalet]

Unlike Katana's DiagnosticsLoggerFactory, the vNext equivalent now requires a TraceListener, which makes the trace source logger a bit painful to use in practice, since you can't simply rely on the listeners defined at the static level (that may be registered via the .config file on .NET Desktop)

Please consider updating TraceSourceLoggerProvider to make this parameter optional and offering a simpler AddTraceSource that doesn't require a specific trace listener.

@davidfowl do you remember why you had removed the parameterless constructor? https://github.com/aspnet/Logging/pull/143/files#diff-ca74d694fa53328497b21b4a9528dae5L28

/cc @muratg

[muratg]

@davidfowl why did we remove this constructor?

[muratg]

Tentatively putting it in 1.0.0. We'll discuss after RC2 ships.

[moozzyk]

Fixed in 5019dd2

[kevinchalet]

@moozzyk thanks!

Quick question: any particular reason to not provide an overload of AddTraceSource taking no TraceListener parameter? Because it's great to make it optional in the provider class itself, but currently, an exception will be thrown if you try to use the AddTraceSource extensions:

https://github.com/aspnet/Logging/blob/dev/src/Microsoft.Extensions.Logging.TraceSource/TraceSourceFactoryExtensions.cs#L27
https://github.com/aspnet/Logging/blob/dev/src/Microsoft.Extensions.Logging.TraceSource/TraceSourceFactoryExtensions.cs#L50