@SagarViradiya If you’re wanting to use Newtonsoft.Json, you’ll need to take a dependency on OpenSearch.Client.JsonNetSerializer and configure the client to use it like so:
new ConnectionSettings(pool, JsonNetSerializer.Default)
// OR, if you want the behaviour of ignoring nulls except when specified:
new ConnectionSettings(pool, (b, v) => new JsonNetSerializer(b, v, () => new JsonSerializerSettings { NullValueHandling = NullValueHandling.Ignore }))