Remove Threading in Sink in favor of Serilog.Sinks.Async?

[Nefarion]

Serilog.Sinks.File for example uses Serilog.Sinks.Async to give the user the choice to either operate on the main thread or in a background thread.

[augustoproiete]

Hey @Nefarion, thanks for the suggestion. What benefits would that give users of this sink? Are you looking for any behavior in particular in terms of UX?