Made changes to allow passing number of frames to be skipped for calc…

[sonaljain14]

…ulation of caller class name, method name and line number. This is to allow proper working with log4net conversion template %C(%M),%line which without this change would return the Log4NetSink(Emit), 0

[nblumhardt]

Thanks for the PR! 👍

Definitely in favor of making the behavioral change, but do we need to expose the skipFrames option as a configuration parameter? It seems like a custom wrapper over Serilog over log4net is a fairly narrow use case. If we leave the WriteTo.Log4Net() method signature unchanged, we don't need to worry about how to deal with a binary (API) breaking change. What do you think?

[sonaljain14]

Thanks for looking into the PR. We actually came across this scenario in one of our projects. We were developing libraries wherein we have a wrapper over serilog. All the new code we write is going to use serilog along with seq. For a few of the assemblies that we are making we need to give them to a team which has to be integrated into a legacy product which is using log4net (again with a wrapper). for that specific reason I thought of passing the skipFrames as a parameter.

[nblumhardt]

Thanks for the follow-up; I just had a deeper look into this - I think the dynamic stack frame construction and reflection are going to be a pretty big per-event performance hit.

Would it work to specify callerStackBoundaryDeclaringType directly on WriteTo.Log4Net()? (For Serilog, this would be Logger).