Fix warnings

dotnet/src/Connectors/Connectors.Memory.AzureCosmosDBNoSQL/AzureCosmosDBNoSQLMemoryStore.cs

@@ -400,7 +400,9 @@ protected virtual void Dispose(bool disposing)
 /// <param name="key"></param>
 /// <param name="timestamp"></param>
 [DebuggerDisplay("{GetDebuggerDisplay()}")]
-internal class MemoryRecordWithSimilarityScore(
+#pragma warning disable CA1812 // 'MemoryRecordWithSimilarityScore' is an internal class that is apparently never instantiated. If so, remove the code from the assembly. If this class is intended to contain only static members, make it 'static' (Module in Visual Basic). (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1812)
+internal sealed class MemoryRecordWithSimilarityScore(
+#pragma warning restore CA1812
     MemoryRecordMetadata metadata,
     ReadOnlyMemory<float> embedding,
     string? key,
@@ -421,7 +423,7 @@ private string GetDebuggerDisplay()
 /// Creates a new record that also serializes an "id" property.
 /// </summary>
 [DebuggerDisplay("{GetDebuggerDisplay()}")]
-internal class MemoryRecordWithId : MemoryRecord
+internal sealed class MemoryRecordWithId : MemoryRecord
 {
     /// <summary>
     /// Creates a new record that also serializes an "id" property.

dotnet/src/Connectors/Connectors.Memory.AzureCosmosDBNoSQL/CosmosSystemTextJSonSerializer.cs

@@ -3,6 +3,7 @@
 // Taken from https://github.com/Azure/azure-cosmos-dotnet-v3/pull/4332
 
 using System;
+using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Reflection;
 using System.Text.Json;
@@ -13,7 +14,7 @@ namespace Microsoft.Azure.Cosmos;
 /// <summary>
 /// This class provides a default implementation of System.Text.Json Cosmos Linq Serializer.
 /// </summary>
-internal class CosmosSystemTextJsonSerializer : CosmosLinqSerializer
+internal sealed class CosmosSystemTextJsonSerializer : CosmosLinqSerializer
 {
     /// <summary>
     /// A read-only instance of <see cref="JsonSerializerOptions"/>.
@@ -32,6 +33,7 @@ internal class CosmosSystemTextJsonSerializer : CosmosLinqSerializer
     }
 
     /// <inheritdoc/>
+    [return: MaybeNull]
     public override T FromStream<T>(Stream stream)
     {
         if (stream == null)
@@ -107,22 +109,22 @@ public override Stream ToStream<T>(T input)
     /// To handle such scenarios, please create a custom serializer which inherits from the <see cref="CosmosSystemTextJsonSerializer"/> and overrides the
     /// SerializeMemberName to add any special handling.
     /// </remarks>
-    public override string SerializeMemberName(MemberInfo memberInfo)
+    public override string? SerializeMemberName(MemberInfo memberInfo)
     {
-        JsonExtensionDataAttribute jsonExtensionDataAttribute =
+        JsonExtensionDataAttribute? jsonExtensionDataAttribute =
              memberInfo.GetCustomAttribute<JsonExtensionDataAttribute>(true);
 
         if (jsonExtensionDataAttribute != null)
         {
             return null;
         }
 
-        JsonPropertyNameAttribute jsonPropertyNameAttribute = memberInfo.GetCustomAttribute<JsonPropertyNameAttribute>(true);
-
-        string memberName = !string.IsNullOrEmpty(jsonPropertyNameAttribute?.Name)
-            ? jsonPropertyNameAttribute.Name
-            : memberInfo.Name;
+        JsonPropertyNameAttribute? jsonPropertyNameAttribute = memberInfo.GetCustomAttribute<JsonPropertyNameAttribute>(true);
+        if (jsonPropertyNameAttribute is { } && !string.IsNullOrEmpty(jsonPropertyNameAttribute.Name))
+        {
+            return jsonPropertyNameAttribute.Name;
+        }
 
-        return memberName;
+        return memberInfo.Name;
     }
 }