enable conveniently overriding json serialization settings without th…

src/Nest/CommonAbstractions/SerializationBehavior/JsonNetSerializer.cs

@@ -30,29 +30,25 @@ protected virtual void ModifyJsonSerializerSettings(JsonSerializerSettings setti
 
 		protected virtual IList<Func<Type, JsonConverter>> ContractConverters => null;
 
-		public JsonNetSerializer(IConnectionSettingsValues settings) : this(settings, null) { }
+		public JsonNetSerializer(IConnectionSettingsValues settings, Action<JsonSerializerSettings, IConnectionSettingsValues> settingsModifier) : this(settings, null, settingsModifier) { }
+
+		public JsonNetSerializer(IConnectionSettingsValues settings) : this(settings, null, null) { }
 
 		/// <summary>
 		/// this constructor is only here for stateful (de)serialization
 		/// </summary>
 		protected internal JsonNetSerializer(
 			IConnectionSettingsValues settings,
-			JsonConverter statefulConverter
+			JsonConverter statefulConverter,
+			Action<JsonSerializerSettings, IConnectionSettingsValues> settingsModifier = null
 			)
 		{
 			this.Settings = settings;
-
 			var piggyBackState = statefulConverter == null ? null : new JsonConverterPiggyBackState { ActualJsonConverter = statefulConverter };
 			// ReSharper disable once VirtualMemberCallInContructor
 			this.ContractResolver = new ElasticContractResolver(this.Settings, this.ContractConverters) { PiggyBackState = piggyBackState };
 
-			this._defaultSerializer = JsonSerializer.Create(this.CreateSettings(SerializationFormatting.None));
-			var indentedSerializer = JsonSerializer.Create(this.CreateSettings(SerializationFormatting.Indented));
-			this._defaultSerializers = new Dictionary<SerializationFormatting, JsonSerializer>
-			{
-				{ SerializationFormatting.None, this._defaultSerializer },
-				{ SerializationFormatting.Indented, indentedSerializer }
-			};
+			OverwriteDefaultSerializers(settingsModifier ?? ((s, csv) => { }));
 		}
 
 		/// <summary>

src/Nest/CommonAbstractions/SerializationBehavior/SerializerFactory.cs

@@ -18,18 +18,24 @@ public interface ISerializerFactory
 	public class SerializerFactory : ISerializerFactory
 	{
 		private Func<IConnectionSettingsValues, IElasticsearchSerializer> _serializerFactoryFunc;
+		private Action<JsonSerializerSettings, IConnectionSettingsValues> _settingsModifier;
 
 		public SerializerFactory()
 		{
 
 		}
-		public SerializerFactory(Func<IConnectionSettingsValues , IElasticsearchSerializer> serializerFactoryFunc)
+		public SerializerFactory(Func<IConnectionSettingsValues, IElasticsearchSerializer> serializerFactoryFunc) : this(serializerFactoryFunc, null) { }
+
+		public SerializerFactory(Action<JsonSerializerSettings, IConnectionSettingsValues> settingsModifier) : this(null, settingsModifier) { }
+
+		public SerializerFactory(Func<IConnectionSettingsValues, IElasticsearchSerializer> serializerFactoryFunc, Action<JsonSerializerSettings, IConnectionSettingsValues> settingsModifier)
 		{
 			this._serializerFactoryFunc = serializerFactoryFunc;
+			this._settingsModifier = settingsModifier;
 		}
 
 		public IElasticsearchSerializer Create(IConnectionSettingsValues settings) =>
-			this._serializerFactoryFunc?.Invoke(settings) ?? new JsonNetSerializer(settings);
+			this._serializerFactoryFunc?.Invoke(settings) ?? new JsonNetSerializer(settings, this._settingsModifier);
 
 		public IElasticsearchSerializer CreateStateful(IConnectionSettingsValues settings, JsonConverter converter) =>
 			new JsonNetSerializer(settings, converter);

src/Tests/ClientConcepts/LowLevel/Connecting.doc.cs

@@ -296,15 +296,18 @@ protected override HttpClientHandler CreateHttpClientHandler(RequestData request
 		*/
 		public class MyJsonNetSerializer : JsonNetSerializer
 		{
-			public MyJsonNetSerializer(IConnectionSettingsValues settings) : base(settings) { }
+			public MyJsonNetSerializer(IConnectionSettingsValues settings) : base(settings, (s, csv) => s.PreserveReferencesHandling = PreserveReferencesHandling.All) //<1> Call this constructor if you only need access to `JsonSerializerSettings` without state
+			{
+				OverwriteDefaultSerializers((s, cvs) => ModifySerializerSettings(s)); //<2> Call OverwriteDefaultSerializers if you need access to `JsonSerializerSettings` with state
+			}
 
 			public int CallToModify { get; set; } = 0;
 
-			protected override void ModifyJsonSerializerSettings(JsonSerializerSettings settings) => ++CallToModify; //<1> Override ModifyJsonSerializerSettings if you need access to `JsonSerializerSettings`
+			private void ModifySerializerSettings(JsonSerializerSettings settings) => ++CallToModify;
 
 			public int CallToContractConverter { get; set; } = 0;
 
-			protected override IList<Func<Type, JsonConverter>> ContractConverters => new List<Func<Type, JsonConverter>> //<2> You can inject contract resolved converters by implementing the ContractConverters property. This can be much faster then registering them on `JsonSerializerSettings.Converters`
+			protected override IList<Func<Type, JsonConverter>> ContractConverters => new List<Func<Type, JsonConverter>> //<3> You can inject contract resolved converters by implementing the ContractConverters property. This can be much faster then registering them on `JsonSerializerSettings.Converters`
 			{
 				t => {
 					CallToContractConverter++;