How to check is session is available/configured

[304NotModified]

With NLog users can log session values (e.g. to file).

In ASP.NET4 this works well, but with this library we have the following issues:

• This could lead to a stackoverflow, as DistributedSession.Load and DistributedSession.LoadAsync also writes log messages - we have made a work around this.
• Reading session could lead to exceptions: System.InvalidOperationException: Session has not been configured for this application or request.

How do we check (without writing a log message) if the session is available/configured, so that we can prevent these issues?

Related #99, https://github.com/NLog/NLog.Extensions.Logging/issues/28

[Tratcher]

To see if it's enabled you can check if context.Features.Get<ISessionFeature>()?.Session != null.

[304NotModified]

Thanks!