Avoid doing multiple dictionary lookups (get key hash, find bucket, iterate bucket)

Forward port of 750b4ec

Author: russcam

src/Elasticsearch.Net/Responses/Sniff/SniffResponse.cs

@@ -78,8 +78,8 @@ internal bool HttpEnabled
 		{
 			get
 			{
-				if (settings != null && settings.ContainsKey("http.enabled"))
-					return Convert.ToBoolean(settings["http.enabled"]);
+				if (settings != null && settings.TryGetValue("http.enabled", out var httpEnabled))
+					return Convert.ToBoolean(httpEnabled);
 
 				return http != null;
 			}

src/Nest/CommonAbstractions/ConnectionSettings/ConnectionSettingsBase.cs

@@ -175,9 +175,9 @@ private void MapIdPropertyFor<TDocument>(Expression<Func<TDocument, object>> obj
 			var memberInfo = new MemberInfoResolver(objectPath);
 			var fieldName = memberInfo.Members.Single().Name;
 
-			if (_idProperties.ContainsKey(typeof(TDocument)))
+			if (_idProperties.TryGetValue(typeof(TDocument), out var idPropertyFieldName))
 			{
-				if (_idProperties[typeof(TDocument)].Equals(fieldName)) return;
+				if (idPropertyFieldName.Equals(fieldName)) return;
 
 				throw new ArgumentException(
 					$"Cannot map '{fieldName}' as the id property for type '{typeof(TDocument).Name}': it already has '{_idProperties[typeof(TDocument)]}' mapped.");
@@ -193,9 +193,9 @@ private void MapRoutePropertyFor<TDocument>(Expression<Func<TDocument, object>>
 			var memberInfo = new MemberInfoResolver(objectPath);
 			var fieldName = memberInfo.Members.Single().Name;
 
-			if (_routeProperties.ContainsKey(typeof(TDocument)))
+			if (_routeProperties.TryGetValue(typeof(TDocument), out var routePropertyFieldName))
 			{
-				if (_routeProperties[typeof(TDocument)].Equals(fieldName)) return;
+				if (routePropertyFieldName.Equals(fieldName)) return;
 
 				throw new ArgumentException(
 					$"Cannot map '{fieldName}' as the route property for type '{typeof(TDocument).Name}': it already has '{_routeProperties[typeof(TDocument)]}' mapped.");
@@ -227,10 +227,10 @@ private void ApplyPropertyMappings<TDocument>(IList<IClrPropertyMapping<TDocumen
 					memberInfo = typeof(TDocument).GetMember(memberInfo.Name, bindingFlags).First();
 				}
 
-				if (_propertyMappings.ContainsKey(memberInfo))
+				if (_propertyMappings.TryGetValue(memberInfo, out var propertyMapping))
 				{
 					var newName = mapping.NewName;
-					var mappedAs = _propertyMappings[memberInfo].Name;
+					var mappedAs = propertyMapping.Name;
 					var typeName = typeof(TDocument).Name;
 					if (mappedAs.IsNullOrEmpty() && newName.IsNullOrEmpty())
 						throw new ArgumentException($"Property mapping '{e}' on type is already ignored");

src/Nest/IndexModules/IndexSettings/Settings/IndexSettingsFormatter.cs

@@ -285,10 +285,9 @@ private static void Set<T>(IIndexSettings s, IDictionary<string, object> setting
 			IJsonFormatterResolver formatterResolver
 		)
 		{
-			if (!settings.ContainsKey(key))
+			if (!settings.TryGetValue(key, out var setting))
 				return;
 
-			var setting = settings[key];
 			var value = ConvertToValue<T>(setting, formatterResolver);
 			assign(value);
 			s.Add(key, value);
@@ -333,9 +332,8 @@ private static void SetArray<TArray, TItem>(IIndexSettings s, IDictionary<string
 		)
 			where TArray : IEnumerable<TItem>
 		{
-			if (!settings.ContainsKey(key)) return;
+			if (!settings.TryGetValue(key, out var v)) return;
 
-			var v = settings[key];
 			if (!(v is string) && v is IEnumerable)
 			{
 				var value = ConvertToValue<TArray>(v, formatterResolver);