Add the ability to not log empty messages

[bspraguetx]

We rely on the Serilog.Expressions package to create custom expressions that are used to control what messages are written to particular sink. If the expression returns false then no message details are emitted to the sink. There is no logic in this sink to bypass writing an empty message. Would you please consider adding an optional switch to the configuration that would bypass writing the message if the rendered payload is an empty string or just whitespace?

Thanks

[mrbcmorris]

Hey @bspraguetx,

Unfortunately I don't have a windows machine setup any longer so I wouldn't be able to help out with this request. I'd be happy to help you through the process of submitting a patch if you're interested in trying to tackle it. There may be some other maintainers hanging around as well who could see this message.