C# Broken changes v2 -> v3 driver for CamelCase

I used the following code to selectively use CamelCase for the JSON method. In v3, I couldn’t find how to do this.

    var jsonWriterSettings = new JsonWriterSettings
    {
        NamingConvention = NamingConvention.CamelCase
    };
    var json = posts.ToJson(jsonWriterSettings);