Removed callvirt-s in BufferWriterStream and AsStream cast

Microsoft.Toolkit.HighPerformance/Extensions/ArrayPoolBufferWriterExtensions.cs

@@ -0,0 +1,32 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Diagnostics.Contracts;
+using System.IO;
+using System.Runtime.CompilerServices;
+using Microsoft.Toolkit.HighPerformance.Buffers;
+using Microsoft.Toolkit.HighPerformance.Streams;
+using Microsoft.Toolkit.HighPerformance.Streams.Sources;
+
+namespace Microsoft.Toolkit.HighPerformance.Extensions
+{
+    /// <summary>
+    /// Helpers for working with the <see cref="ArrayPoolBufferWriter{T}"/> type.
+    /// </summary>
+    public static class ArrayPoolBufferWriterExtensions
+    {
+        /// <summary>
+        /// Returns a <see cref="Stream"/> that can be used to write to a target an <see cref="ArrayPoolBufferWriter{T}"/> of <see cref="byte"/> instance.
+        /// </summary>
+        /// <param name="writer">The target <see cref="ArrayPoolBufferWriter{T}"/> instance.</param>
+        /// <returns>A <see cref="Stream"/> wrapping <paramref name="writer"/> and writing data to its underlying buffer.</returns>
+        /// <remarks>The returned <see cref="Stream"/> can only be written to and does not support seeking.</remarks>
+        [Pure]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static Stream AsStream(this ArrayPoolBufferWriter<byte> writer)
+        {
+            return new IBufferWriterStream<ArrayBufferWriterOwner>(new ArrayBufferWriterOwner(writer));
+        }
+    }
+}

Microsoft.Toolkit.HighPerformance/Extensions/IBufferWriterExtensions.cs

@@ -9,6 +9,7 @@ using System.IO;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using Microsoft.Toolkit.HighPerformance.Streams;
+using Microsoft.Toolkit.HighPerformance.Streams.Sources;
 
 namespace Microsoft.Toolkit.HighPerformance.Extensions
 {
@@ -18,16 +19,16 @@ namespace Microsoft.Toolkit.HighPerformance.Extensions
     public static class IBufferWriterExtensions
     {
         /// <summary>
-        /// Returns a <see cref="Stream"/> that can be used to write to a target <see cref="IBufferWriter{T}"/> of <see cref="byte"/> instance.
+        /// Returns a <see cref="Stream"/> that can be used to write to a target an <see cref="IBufferWriter{T}"/> of <see cref="byte"/> instance.
         /// </summary>
-        /// <param name="writer">The target <see cref="Memory{T}"/> of <see cref="byte"/> instance.</param>
+        /// <param name="writer">The target <see cref="IBufferWriter{T}"/> instance.</param>
         /// <returns>A <see cref="Stream"/> wrapping <paramref name="writer"/> and writing data to its underlying buffer.</returns>
         /// <remarks>The returned <see cref="Stream"/> can only be written to and does not support seeking.</remarks>
         [Pure]
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static Stream AsStream(this IBufferWriter<byte> writer)
         {
-            return new IBufferWriterStream(writer);
+            return new IBufferWriterStream<IBufferWriterOwner>(new IBufferWriterOwner(writer));
         }
 
         /// <summary>

Microsoft.Toolkit.HighPerformance/Streams/IBufferWriterStream{TWriter}.Memory.cs

@@ -11,8 +11,8 @@ using System.Threading.Tasks;
 
 namespace Microsoft.Toolkit.HighPerformance.Streams
 {
-    /// <inheritdoc cref="IBufferWriterStream"/>
-    internal sealed partial class IBufferWriterStream
+    /// <inheritdoc cref="IBufferWriterStream{TWriter}"/>
+    internal sealed partial class IBufferWriterStream<TWriter>
     {
         /// <inheritdoc/>
         public override void CopyTo(Stream destination, int bufferSize)

Microsoft.Toolkit.HighPerformance/Streams/IBufferWriterStream{TWriter}.cs

@@ -14,12 +14,14 @@ namespace Microsoft.Toolkit.HighPerformance.Streams
     /// <summary>
     /// A <see cref="Stream"/> implementation wrapping an <see cref="IBufferWriter{T}"/> instance.
     /// </summary>
-    internal sealed partial class IBufferWriterStream : Stream
+    /// <typeparam name="TWriter">The type of buffer writer to use.</typeparam>
+    internal sealed partial class IBufferWriterStream<TWriter> : Stream
+        where TWriter : struct, IBufferWriter<byte>
     {
         /// <summary>
-        /// The target <see cref="IBufferWriter{T}"/> instance to use.
+        /// The target <typeparamref name="TWriter"/> instance to use.
         /// </summary>
-        private readonly IBufferWriter<byte> bufferWriter;
+        private readonly TWriter bufferWriter;
 
         /// <summary>
         /// Indicates whether or not the current instance has been disposed
@@ -27,10 +29,10 @@ namespace Microsoft.Toolkit.HighPerformance.Streams
         private bool disposed;
 
         /// <summary>
-        /// Initializes a new instance of the <see cref="IBufferWriterStream"/> class.
+        /// Initializes a new instance of the <see cref="IBufferWriterStream{TWriter}"/> class.
         /// </summary>
         /// <param name="bufferWriter">The target <see cref="IBufferWriter{T}"/> instance to use.</param>
-        public IBufferWriterStream(IBufferWriter<byte> bufferWriter)
+        public IBufferWriterStream(TWriter bufferWriter)
         {
             this.bufferWriter = bufferWriter;
         }

Microsoft.Toolkit.HighPerformance/Streams/Sources/ArrayBufferWriterOwner.cs

@@ -0,0 +1,52 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Buffers;
+using System.Runtime.CompilerServices;
+using Microsoft.Toolkit.HighPerformance.Buffers;
+
+namespace Microsoft.Toolkit.HighPerformance.Streams.Sources
+{
+    /// <summary>
+    /// An <see cref="IBufferWriter{T}"/> implementation wrapping an <see cref="ArrayPoolBufferWriter{T}"/> instance.
+    /// </summary>
+    internal readonly struct ArrayBufferWriterOwner : IBufferWriter<byte>
+    {
+        /// <summary>
+        /// The wrapped <see cref="ArrayPoolBufferWriter{T}"/> array.
+        /// </summary>
+        private readonly ArrayPoolBufferWriter<byte> writer;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ArrayBufferWriterOwner"/> struct.
+        /// </summary>
+        /// <param name="writer">The wrapped <see cref="ArrayPoolBufferWriter{T}"/> instance.</param>
+        public ArrayBufferWriterOwner(ArrayPoolBufferWriter<byte> writer)
+        {
+            this.writer = writer;
+        }
+
+        /// <inheritdoc/>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public void Advance(int count)
+        {
+            this.writer.Advance(count);
+        }
+
+        /// <inheritdoc/>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public Memory<byte> GetMemory(int sizeHint = 0)
+        {
+            return this.writer.GetMemory(sizeHint);
+        }
+
+        /// <inheritdoc/>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public Span<byte> GetSpan(int sizeHint = 0)
+        {
+            return this.writer.GetSpan(sizeHint);
+        }
+    }
+}

Microsoft.Toolkit.HighPerformance/Streams/Sources/IBufferWriterOwner.cs

@@ -0,0 +1,52 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Buffers;
+using System.Runtime.CompilerServices;
+using Microsoft.Toolkit.HighPerformance.Buffers;
+
+namespace Microsoft.Toolkit.HighPerformance.Streams.Sources
+{
+    /// <summary>
+    /// An <see cref="IBufferWriter{T}"/> implementation wrapping an <see cref="IBufferWriter{T}"/> instance.
+    /// </summary>
+    internal readonly struct IBufferWriterOwner : IBufferWriter<byte>
+    {
+        /// <summary>
+        /// The wrapped <see cref="ArrayPoolBufferWriter{T}"/> array.
+        /// </summary>
+        private readonly IBufferWriter<byte> writer;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="IBufferWriterOwner"/> struct.
+        /// </summary>
+        /// <param name="writer">The wrapped <see cref="IBufferWriter{T}"/> instance.</param>
+        public IBufferWriterOwner(IBufferWriter<byte> writer)
+        {
+            this.writer = writer;
+        }
+
+        /// <inheritdoc/>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public void Advance(int count)
+        {
+            this.writer.Advance(count);
+        }
+
+        /// <inheritdoc/>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public Memory<byte> GetMemory(int sizeHint = 0)
+        {
+            return this.writer.GetMemory(sizeHint);
+        }
+
+        /// <inheritdoc/>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public Span<byte> GetSpan(int sizeHint = 0)
+        {
+            return this.writer.GetSpan(sizeHint);
+        }
+    }
+}