.Net: Add Async Support for ConverseStreamResponse to Avoid Thread Bl…

…ocking (#10159)

### Motivation and Context

This change replaces the use of `response.Stream.AsEnumerable()` with
`await foreach` for async streaming in the Amazon Bedrock SDK. The
previous method blocked the calling thread, leading to potential thread
exhaustion in high-concurrency scenarios. This update aligns with best
practices for asynchronous operations in .NET.

### Description

- Replaced blocking foreach with `await foreach` for streaming
`ConverseStreamResponse` chunks asynchronously.
- Upgraded Amazon Bedrock runtime and core SDKs to support this
functionality.

### Contribution Checklist

- [Y] The code builds clean without any errors or warnings
- [Y] The PR follows the [SK Contribution
Guidelines](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
and the [pre-submission formatting
script](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md#development-scripts)
raises no violations
- [Y] All unit tests pass, and I have added new tests where possible
- [Y] I didn't break anyone 😄

Fixes #9519

---------

Co-authored-by: Adit Sheth <[email protected]>

dotnet/Directory.Packages.props

@@ -5,9 +5,9 @@
     <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
   </PropertyGroup>
   <ItemGroup>
-    <PackageVersion Include="AWSSDK.BedrockRuntime" Version="3.7.411.5" />
+    <PackageVersion Include="AWSSDK.BedrockRuntime" Version="4.0.0-preview.5" />
     <PackageVersion Include="AWSSDK.Extensions.NETCore.Setup" Version="3.7.301" />
-    <PackageVersion Include="AWSSDK.Core" Version="3.7.400.64" />
+    <PackageVersion Include="AWSSDK.Core" Version="4.0.0-preview.5" />
     <PackageVersion Include="Azure.AI.Inference" Version="1.0.0-beta.2" />
     <PackageVersion Include="Dapr.Actors" Version="1.14.0" />
     <PackageVersion Include="Dapr.Actors.AspNetCore" Version="1.14.0" />
@@ -165,4 +165,4 @@
     <PackageVersion Include="Microsoft.ML.OnnxRuntimeGenAI.Cuda" Version="0.5.2" />
     <PackageVersion Include="Microsoft.ML.OnnxRuntimeGenAI.DirectML" Version="0.5.2" />
   </ItemGroup>
-</Project>
+</Project>

dotnet/src/Connectors/Connectors.Amazon/Bedrock/Core/Clients/BedrockChatCompletionClient.cs

@@ -76,8 +76,8 @@ internal async Task<IReadOnlyList<ChatMessageContent>> GenerateChatMessageAsync(
             {
                 activityStatus = BedrockClientUtilities.ConvertHttpStatusCodeToActivityStatusCode(response.HttpStatusCode);
                 activity.SetStatus(activityStatus);
-                activity.SetPromptTokenUsage(response.Usage.InputTokens);
-                activity.SetCompletionTokenUsage(response.Usage.OutputTokens);
+                activity.SetPromptTokenUsage(response?.Usage?.InputTokens ?? default);
+                activity.SetCompletionTokenUsage(response?.Usage?.OutputTokens ?? default);
             }
         }
         catch (Exception ex)
@@ -90,8 +90,8 @@ internal async Task<IReadOnlyList<ChatMessageContent>> GenerateChatMessageAsync(
                 {
                     activityStatus = BedrockClientUtilities.ConvertHttpStatusCodeToActivityStatusCode(response.HttpStatusCode);
                     activity.SetStatus(activityStatus);
-                    activity.SetPromptTokenUsage(response.Usage.InputTokens);
-                    activity.SetCompletionTokenUsage(response.Usage.OutputTokens);
+                    activity.SetPromptTokenUsage(response?.Usage?.InputTokens ?? default);
+                    activity.SetCompletionTokenUsage(response?.Usage?.OutputTokens ?? default);
                 }
                 else
                 {
@@ -191,7 +191,7 @@ internal async IAsyncEnumerable<StreamingChatMessageContent> StreamChatMessageAs
             throw;
         }
         List<StreamingChatMessageContent>? streamedContents = activity is not null ? [] : null;
-        foreach (var chunk in response.Stream.AsEnumerable())
+        await foreach (var chunk in response.Stream.ConfigureAwait(false))
         {
             if (chunk is ContentBlockDeltaEvent deltaEvent)
             {