Update Servers' Obsolete messages and comments

src/Servers/IIS/IIS/src/BadHttpRequestException.cs

@@ -9,7 +9,7 @@
 namespace Microsoft.AspNetCore.Server.IIS
 {
     ///<inheritdoc/>
-    [Obsolete("Moved to Microsoft.AspNetCore.Http.BadHttpRequestException")]
+    [Obsolete("Moved to Microsoft.AspNetCore.Http.BadHttpRequestException. See https://aka.ms/badhttprequestexception for details.")] // Never remove.
     public sealed class BadHttpRequestException : Microsoft.AspNetCore.Http.BadHttpRequestException
     {
         internal BadHttpRequestException(string message, int statusCode, RequestRejectionReason reason)

src/Servers/IIS/IIS/src/Core/IISServerAuthenticationHandler.cs

@@ -12,7 +12,7 @@ namespace Microsoft.AspNetCore.Server.IIS.Core
     /// <summary>
     /// The default authentication handler with IIS In-Process
     /// </summary>
-    [Obsolete("The IISServerAuthenticationHandler is obsolete and will be removed in a future release.")]
+    [Obsolete("The IISServerAuthenticationHandler is obsolete and will be removed in a future release.")] // Remove after .NET 6.
     public class IISServerAuthenticationHandler : IAuthenticationHandler
     {
         private HttpContext? _context;

src/Servers/IIS/IIS/src/Core/ThrowingWasUpgradedWriteOnlyStream.cs

@@ -14,7 +14,7 @@ namespace Microsoft.AspNetCore.Server.IIS.Core
     /// <remarks>
     /// Users should not need to instantiate this class.
     /// </remarks>
-    [Obsolete("The ThrowingWasUpgradedWriteOnlyStream is obsolete and will be removed in a future release.")]
+    [Obsolete("The ThrowingWasUpgradedWriteOnlyStream is obsolete and will be removed in a future release.")] // Remove after .NET 6.
     public class ThrowingWasUpgradedWriteOnlyStream : WriteOnlyStream
     {
         ///<inheritdoc/>

src/Servers/IIS/IIS/src/Core/WrappingStream.cs

@@ -107,9 +107,10 @@ public override int EndRead(IAsyncResult asyncResult)
         public override void EndWrite(IAsyncResult asyncResult)
             => _inner.EndWrite(asyncResult);
 
-        [Obsolete("This Remoting API is not supported and throws PlatformNotSupportedException.", DiagnosticId = "SYSLIB0010", UrlFormat = "https://aka.ms/dotnet-warnings/{0}")]
+#pragma warning disable CS0672, SYSLIB0010 // Overrides obsolete member
         public override object InitializeLifetimeService()
             => _inner.InitializeLifetimeService();
+#pragma warning restore CS0672, SYSLIB0010 // Overrides obsolete member
 
         public override void Close()
             => _inner.Close();

src/Servers/IIS/IIS/src/Core/WriteOnlyStream.cs

@@ -11,7 +11,7 @@ namespace Microsoft.AspNetCore.Server.IIS.Core
     /// <summary>
     /// A <see cref="Stream"/> which only allows for writes.
     /// </summary>
-    [Obsolete("The WriteOnlyStream is obsolete and will be removed in a future release.")]
+    [Obsolete("The WriteOnlyStream is obsolete and will be removed in a future release.")] // Remove after .NET 6.
     public abstract class WriteOnlyStream : Stream
     {
         ///<inheritdoc/>

src/Servers/IIS/IIS/src/HttpContextExtensions.cs

@@ -21,7 +21,8 @@ public static class HttpContextExtensions
         /// <c>null</c> if the server does not support the <see cref="IServerVariablesFeature"/> feature.
         /// May return null or empty if the variable does not exist or is not set.
         /// </returns>
-        [Obsolete("This is obsolete and will be removed in a future version. Use " + nameof(HttpContextServerVariableExtensions.GetServerVariable) + " instead.")]
+        [Obsolete("This is obsolete and will be removed in a future version. Use " +
+            nameof(HttpContextServerVariableExtensions.GetServerVariable) + " instead.")] // Never remove.
         public static string? GetIISServerVariable(this HttpContext context, string variableName) =>
             context.GetServerVariable(variableName);
     }

src/Servers/Kestrel/Core/src/BadHttpRequestException.cs

@@ -11,7 +11,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core
     /// <summary>
     /// An exception thrown when a malformed http request has been received.
     /// </summary>
-    [Obsolete("Moved to Microsoft.AspNetCore.Http.BadHttpRequestException")]
+    [Obsolete("Moved to Microsoft.AspNetCore.Http.BadHttpRequestException. See https://aka.ms/badhttprequestexception for details.")] // Never remove.
     public sealed class BadHttpRequestException : Microsoft.AspNetCore.Http.BadHttpRequestException
     {
         internal BadHttpRequestException(string message, int statusCode, RequestRejectionReason reason)

src/Servers/Kestrel/Core/src/Internal/Infrastructure/WrappingStream.cs

@@ -107,9 +107,10 @@ public override int EndRead(IAsyncResult asyncResult)
         public override void EndWrite(IAsyncResult asyncResult)
             => _inner.EndWrite(asyncResult);
 
-        [Obsolete("This Remoting API is not supported and throws PlatformNotSupportedException.", DiagnosticId = "SYSLIB0010", UrlFormat = "https://aka.ms/dotnet-warnings/{0}")]
+#pragma warning disable CS0672, SYSLIB0010 // Overrides obsolete member
         public override object InitializeLifetimeService()
             => _inner.InitializeLifetimeService();
+#pragma warning restore CS0672, SYSLIB0010 // Overrides obsolete member
 
         public override void Close()
             => _inner.Close();

src/Servers/Kestrel/Transport.Libuv/src/LibuvTransportOptions.cs

@@ -9,7 +9,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv
     /// <summary>
     /// Provides programmatic configuration of Libuv transport features.
     /// </summary>
-    [Obsolete("The libuv transport is obsolete and will be removed in a future release. See https://aka.ms/libuvtransport for details.", error: false)]
+    [Obsolete("The libuv transport is obsolete and will be removed in a future release. See https://aka.ms/libuvtransport for details.", error: false)] // Remove after .NET 6.
     public class LibuvTransportOptions
     {
         /// <summary>
@@ -18,7 +18,7 @@ public class LibuvTransportOptions
         /// <remarks>
         /// Defaults to half of <see cref="Environment.ProcessorCount" /> rounded down and clamped between 1 and 16.
         /// </remarks>
-        [Obsolete("The libuv transport is obsolete and will be removed in a future release. See https://aka.ms/libuvtransport for details.", error: false)]
+        [Obsolete("The libuv transport is obsolete and will be removed in a future release. See https://aka.ms/libuvtransport for details.", error: false)] // Remove after .NET 6.
         public int ThreadCount { get; set; } = ProcessorThreadCount;
 
         /// <summary>
@@ -27,7 +27,7 @@ public class LibuvTransportOptions
         /// <remarks>
         /// Defaults to true.
         /// </remarks>
-        [Obsolete("The libuv transport is obsolete and will be removed in a future release. See https://aka.ms/libuvtransport for details.", error: false)]
+        [Obsolete("The libuv transport is obsolete and will be removed in a future release. See https://aka.ms/libuvtransport for details.", error: false)] // Remove after .NET 6.
         public bool NoDelay { get; set; } = true;
 
         /// <summary>
@@ -36,13 +36,13 @@ public class LibuvTransportOptions
         /// <remarks>
         /// Defaults to 128.
         /// </remarks>
-        [Obsolete("The libuv transport is obsolete and will be removed in a future release. See https://aka.ms/libuvtransport for details.", error: false)]
+        [Obsolete("The libuv transport is obsolete and will be removed in a future release. See https://aka.ms/libuvtransport for details.", error: false)] // Remove after .NET 6.
         public int Backlog { get; set; } = 128;
 
-        [Obsolete("The libuv transport is obsolete and will be removed in a future release. See https://aka.ms/libuvtransport for details.", error: false)]
+        [Obsolete("The libuv transport is obsolete and will be removed in a future release. See https://aka.ms/libuvtransport for details.", error: false)] // Remove after .NET 6.
         public long? MaxReadBufferSize { get; set; } = 1024 * 1024;
 
-        [Obsolete("The libuv transport is obsolete and will be removed in a future release. See https://aka.ms/libuvtransport for details.", error: false)]
+        [Obsolete("The libuv transport is obsolete and will be removed in a future release. See https://aka.ms/libuvtransport for details.", error: false)] // Remove after .NET 6.
         public long? MaxWriteBufferSize { get; set; } = 64 * 1024;
 
         internal Func<MemoryPool<byte>> MemoryPoolFactory { get; set; } = System.Buffers.SlabMemoryPoolFactory.Create;

src/Servers/Kestrel/Transport.Libuv/src/WebHostBuilderLibuvExtensions.cs

@@ -12,7 +12,7 @@ namespace Microsoft.AspNetCore.Hosting
     /// <summary>
     /// Libuv <see cref="IWebHostBuilder"/> extensions.
     /// </summary>
-    [Obsolete("The libuv transport is obsolete and will be removed in a future release. See https://aka.ms/libuvtransport for details.", error: false)]
+    [Obsolete("The libuv transport is obsolete and will be removed in a future release. See https://aka.ms/libuvtransport for details.", error: false)] // Remove after .NET 6.
     public static class WebHostBuilderLibuvExtensions
     {
         /// <summary>
@@ -24,7 +24,7 @@ public static class WebHostBuilderLibuvExtensions
         /// <returns>
         /// The Microsoft.AspNetCore.Hosting.IWebHostBuilder.
         /// </returns>
-        [Obsolete("The libuv transport is obsolete and will be removed in a future release. See https://aka.ms/libuvtransport for details.", error: false)]
+        [Obsolete("The libuv transport is obsolete and will be removed in a future release. See https://aka.ms/libuvtransport for details.", error: false)] // Remove after .NET 6.
         public static IWebHostBuilder UseLibuv(this IWebHostBuilder hostBuilder)
         {
             return hostBuilder.ConfigureServices(services =>
@@ -45,7 +45,7 @@ public static IWebHostBuilder UseLibuv(this IWebHostBuilder hostBuilder)
         /// <returns>
         /// The Microsoft.AspNetCore.Hosting.IWebHostBuilder.
         /// </returns>
-        [Obsolete("The libuv transport is obsolete and will be removed in a future release. See https://aka.ms/libuvtransport for details.", error: false)]
+        [Obsolete("The libuv transport is obsolete and will be removed in a future release. See https://aka.ms/libuvtransport for details.", error: false)] // Remove after .NET 6.
         public static IWebHostBuilder UseLibuv(this IWebHostBuilder hostBuilder, Action<LibuvTransportOptions> configureOptions)
         {
             return hostBuilder.UseLibuv().ConfigureServices(services =>