title: How to set formatProvider property in Serilog from app.config file
body: <p>I know that it's possible to setup Serilog sinks in app.config file (<a href="https://github.com/serilog/serilog/wiki/AppSettings" rel="nofollow">AppSettings</a> section) and it's pretty simple with scalar types, but how to be with complex ones (IFormatProvider etc.). Does anybody know how to deal with that and is it possible at all? </p>
  
  <p>I'm trying to simulate this example </p>
  
  <pre><code>ILogger logger = new LoggerConfiguration()
      .Enrich.WithExceptionDetails()
      .WriteTo.Sink(new RollingFileSink(
          @"C:\logs",
          new JsonFormatter(renderMessage: true))
      .CreateLogger();
  </code></pre>
  
  <p>but using app.config only. </p>