Update preview flag with message

Author: normj

Libraries/src/Amazon.Lambda.AspNetCoreServer.Hosting/HostingOptions.cs

@@ -9,6 +9,12 @@ namespace Amazon.Lambda.AspNetCoreServer.Hosting;
 /// </summary>
 public class HostingOptions
 {
+    internal const string ParameterizedPreviewMessage =
+        "Response streaming is in preview till a new version of .NET Lambda runtime client that supports response streaming " +
+        "has been deployed to the .NET Lambda managed runtime. Till deployment has been made the feature can be used by deploying as an " +
+        "executable including the latest version of Amazon.Lambda.RuntimeSupport and setting the \"EnablePreviewFeatures\" in the Lambda " +
+        "project file to \"true\"";
+
     /// <summary>
     /// The ILambdaSerializer used by Lambda to convert the incoming event JSON into the .NET event type and serialize the .NET response type
     /// back to JSON to return to Lambda.
@@ -32,7 +38,7 @@ public class HostingOptions
     /// instead of <c>FunctionHandlerAsync</c>, enabling Lambda response streaming.
     /// Requires net8.0 or later.
     /// </summary>
-    [System.Runtime.Versioning.RequiresPreviewFeatures]
+    [System.Runtime.Versioning.RequiresPreviewFeatures(ParameterizedPreviewMessage)]
     public bool EnableResponseStreaming { get; set; } = false;
 
     /// <summary>

Libraries/src/Amazon.Lambda.AspNetCoreServer/AbstractAspNetCoreFunction.cs

@@ -24,6 +24,12 @@ namespace Amazon.Lambda.AspNetCoreServer
     /// </summary>
     public abstract class AbstractAspNetCoreFunction
     {
+        internal const string ParameterizedPreviewMessage =
+            "Response streaming is in preview till a new version of .NET Lambda runtime client that supports response streaming " +
+            "has been deployed to the .NET Lambda managed runtime. Till deployment has been made the feature can be used by deploying as an " +
+            "executable including the latest version of Amazon.Lambda.RuntimeSupport and setting the \"EnablePreviewFeatures\" in the Lambda " +
+            "project file to \"true\"";
+
         /// <summary>
         /// Key to access the ILambdaContext object from the HttpContext.Items collection.
         /// </summary>
@@ -200,7 +206,7 @@ public void RegisterResponseContentEncodingForContentEncoding(string contentEnco
         /// buffering it and returning a typed response object (which will be <c>null</c>).
         /// Requires net8.0 or later.
         /// </summary>
-        [System.Runtime.Versioning.RequiresPreviewFeatures]
+        [System.Runtime.Versioning.RequiresPreviewFeatures(ParameterizedPreviewMessage)]
         public virtual bool EnableResponseStreaming { get; set; } = false;
 
 
@@ -683,7 +689,7 @@ protected virtual void PostMarshallResponseFeature(IHttpResponseFeature aspNetCo
         /// </summary>
         /// <param name="responseFeature">The ASP.NET Core response feature for the current invocation.</param>
         /// <returns>A populated <see cref="Amazon.Lambda.Core.ResponseStreaming.HttpResponseStreamPrelude"/>.</returns>
-        [System.Runtime.Versioning.RequiresPreviewFeatures]
+        [System.Runtime.Versioning.RequiresPreviewFeatures(ParameterizedPreviewMessage)]
         protected virtual Amazon.Lambda.Core.ResponseStreaming.HttpResponseStreamPrelude BuildStreamingPrelude(IHttpResponseFeature responseFeature)
         {
             var prelude = new Amazon.Lambda.Core.ResponseStreaming.HttpResponseStreamPrelude
@@ -717,7 +723,7 @@ protected virtual Amazon.Lambda.Core.ResponseStreaming.HttpResponseStreamPrelude
         /// </summary>
         /// <param name="prelude">The HTTP response prelude containing status code and headers.</param>
         /// <returns>A writable <see cref="System.IO.Stream"/> for the response body.</returns>
-        [System.Runtime.Versioning.RequiresPreviewFeatures]
+        [System.Runtime.Versioning.RequiresPreviewFeatures(ParameterizedPreviewMessage)]
         protected virtual System.IO.Stream CreateLambdaResponseStream(
             Amazon.Lambda.Core.ResponseStreaming.HttpResponseStreamPrelude prelude)
         {
@@ -729,7 +735,7 @@ protected virtual System.IO.Stream CreateLambdaResponseStream(
         /// <see cref="EnableResponseStreaming"/> is <c>true</c>. Writes the response directly to a
         /// <see cref="Amazon.Lambda.Core.ResponseStreaming.LambdaResponseStream"/>.
         /// </summary>
-        [System.Runtime.Versioning.RequiresPreviewFeatures]
+        [System.Runtime.Versioning.RequiresPreviewFeatures(ParameterizedPreviewMessage)]
         private async Task ExecuteStreamingRequestAsync(InvokeFeatures features, TREQUEST request, ILambdaContext lambdaContext)
         {
             var responseFeature = (IHttpResponseFeature)features;

Libraries/src/Amazon.Lambda.AspNetCoreServer/Internal/StreamingResponseBodyFeature.cs

@@ -20,11 +20,7 @@ namespace Amazon.Lambda.AspNetCoreServer.Internal
     /// <see cref="MemoryStream"/>; after <see cref="StartAsync"/> all writes go directly to the
     /// <see cref="LambdaResponseStream"/> obtained from the stream opener delegate.
     /// </summary>
-    [RequiresPreviewFeatures(
-        "Response streaming is in preview till a new version of .NET Lambda runtime client that supports response streaming " +
-        "has been deployed to the .NET Lambda managed runtime. Till deployment has been made the feature can be used by deploying as an " +
-        "executable including the latest version of Amazon.Lambda.RuntimeSupport and setting the \"EnablePreviewFeatures\" in the Lambda " +
-        "project file to \"true\"")]
+    [RequiresPreviewFeatures(AbstractAspNetCoreFunction.ParameterizedPreviewMessage)]
     internal class StreamingResponseBodyFeature : IHttpResponseBodyFeature
     {
         private readonly ILogger _logger;