[code-simplifier] simplify: use indexer-style dict initializer and inline lambdas in SerializerUtilities

src/Platform/Microsoft.Testing.Platform/ServerMode/JsonRpc/SerializerUtilities.TestNodeSerializers.cs

@@ -30,27 +30,17 @@ private static void RegisterTestNodeSerializers()
             [JsonRpcStrings.Attachments] = res.Artifacts.Select(f => Serialize(f)).ToList<object>(),
         });
 
-        Serializers[typeof(TestNodeUpdateMessage)] = new ObjectSerializer<TestNodeUpdateMessage>(ev =>
+        Serializers[typeof(TestNodeUpdateMessage)] = new ObjectSerializer<TestNodeUpdateMessage>(ev => new Dictionary<string, object?>
         {
-            Dictionary<string, object?> values = new()
-            {
-                [JsonRpcStrings.Node] = Serialize(ev.TestNode),
-                [JsonRpcStrings.Parent] = ev.ParentTestNodeUid?.Value,
-            };
-
-            return values;
+            [JsonRpcStrings.Node] = Serialize(ev.TestNode),
+            [JsonRpcStrings.Parent] = ev.ParentTestNodeUid?.Value,
         });
 
         // Serialize event types.
-        Serializers[typeof(TestNodeStateChangedEventArgs)] = new ObjectSerializer<TestNodeStateChangedEventArgs>(ev =>
+        Serializers[typeof(TestNodeStateChangedEventArgs)] = new ObjectSerializer<TestNodeStateChangedEventArgs>(ev => new Dictionary<string, object?>
         {
-            Dictionary<string, object?> values = new()
-            {
-                [JsonRpcStrings.RunId] = ev.RunId,
-                [JsonRpcStrings.Changes] = ev.Changes?.Select(ch => Serialize(ch)).ToList<object>(),
-            };
-
-            return values;
+            [JsonRpcStrings.RunId] = ev.RunId,
+            [JsonRpcStrings.Changes] = ev.Changes?.Select(ch => Serialize(ch)).ToList<object>(),
         });
 
         Serializers[typeof(TestNode)] = new ObjectSerializer<TestNode>(

src/Platform/Microsoft.Testing.Platform/ServerMode/JsonRpc/SerializerUtilities.cs

@@ -19,14 +19,8 @@ static SerializerUtilities()
         Deserializers = [];
 
         Serializers[typeof(object)] = new ObjectSerializer<object>(_ => new Dictionary<string, object?>());
-        Serializers[typeof(KeyValuePair<string, string>)] = new ObjectSerializer<KeyValuePair<string, string>>(o =>
-        {
-            Dictionary<string, object?> values = new()
-            {
-                { o.Key, o.Value },
-            };
-            return values;
-        });
+        Serializers[typeof(KeyValuePair<string, string>)] = new ObjectSerializer<KeyValuePair<string, string>>(
+            o => new Dictionary<string, object?> { [o.Key] = o.Value });
 
         RegisterRpcMessageSerializers();
         RegisterTestNodeSerializers();