Added IBufferWriter<byte>.AsStream extension

Author: Sergio0694

Microsoft.Toolkit.HighPerformance/Extensions/IBufferWriterExtensions.cs

@@ -4,8 +4,11 @@
 
 using System;
 using System.Buffers;
+using System.Diagnostics.Contracts;
+using System.IO;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
+using Microsoft.Toolkit.HighPerformance.Streams;
 
 namespace Microsoft.Toolkit.HighPerformance.Extensions
 {
@@ -14,6 +17,19 @@ namespace Microsoft.Toolkit.HighPerformance.Extensions
     /// </summary>
     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.
+        /// </summary>
+        /// <param name="writer">The target <see cref="Memory{T}"/> of <see cref="byte"/> 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);
+        }
+
         /// <summary>
         /// Writes a value of a specified type into a target <see cref="IBufferWriter{T}"/> instance.
         /// </summary>