C# JSON Serialization and Deserialization: An Interesting Configuration

From ServerlessWorkflow, I learned an interesting configuration for NewtonsoftJson.

            var newtonsoftJsonDefaultConfig = (JsonSerializerSettings settings) =>
            {
                settings.ContractResolver = new NonPublicSetterContractResolver();
                settings.NullValueHandling = NullValueHandling.Ignore;
                settings.DefaultValueHandling = DefaultValueHandling.Ignore;
            };
            var defaultSettings = JsonConvert.DefaultSettings;
            JsonConvert.DefaultSettings = () =>
            {
                var settings = defaultSettings?.Invoke();
                if (settings == null)
                    settings = new();
                newtonsoftJsonDefaultConfig(settings);
                return settings;
            };
            services.AddNewtonsoftJsonSerializer(options =>
            {
                newtonsoftJsonDefaultConfig(options);
            });