Nest.JsonSerializerSettings.NullValueHandling not respected

NEST/Elasticsearch.Net version: 6.8.0

Elasticsearch version: AWS Managed 6.7

Description of the problem including expected versus actual behavior: I want my document persisted in Elastic Search to remove properties with null value. This was working before adding the Nest.JsonNetSerializer nuget package but I had issue serializing dynamic types correctly.

Steps to reproduce:

1. Add the below code to create an IElasticClient specifically the sourceSerializer delegate with JsonSerializerSettings.NullValueHandling = NullValueHandling.Ignore

private static IElasticClient CreateElasticClient(
            string searchUri,
            IDocumentMappings documentMappings,
            bool prettyJson = false, 
            bool alwaysThrowExceptions = true,
            int maximumRetries = 3,
            TimeSpan? maxRetryTimeout = null,
            string awsHttpConnectionRegion = null)
        {
            var nodeUri = new Uri(searchUri);
            var retryTimeout = maxRetryTimeout ?? TimeSpan.FromSeconds(15);
            var httpConnection = awsHttpConnectionRegion.IsNullOrEmpty() ? new HttpConnection() : new AwsHttpConnection(awsHttpConnectionRegion);
            var singleNodeConnectionPool = new SingleNodeConnectionPool(nodeUri);
            
            var settings = new ConnectionSettings(
                singleNodeConnectionPool, 
                httpConnection, 
                sourceSerializer: (builtin, serializationSettings) => new JsonNetSerializer(
                    builtin, serializationSettings,
                    () => new JsonSerializerSettings
                    {
                        NullValueHandling = NullValueHandling.Ignore
                    },
                    resolver => resolver.NamingStrategy = new CamelCaseNamingStrategy()))
                .DefaultIndex(documentMappings.IndexStrategy)
                .DefaultTypeName(documentMappings.TypeName)
                .ThrowExceptions(alwaysThrowExceptions)
                .DisableDirectStreaming()
                .MaximumRetries(maximumRetries)
                .MaxRetryTimeout(retryTimeout);

            if (prettyJson)
            {
                settings.PrettyJson();
            }

            return new ElasticClient(settings);
        }

[russcam]

@george-weare8 We’re closing this issue due to inactivity; if you’re still in need of resolution, feel free to re-open with the additional details and we’d be glad to help you out 👍

[russcam]

@george-weare8 any further details that you can provide for this?