ReadOnlySpan goodness (#8392)

Author: benaadams

src/Servers/Kestrel/Core/src/Internal/Http/HttpResponseHeaders.cs

@@ -14,8 +14,8 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
 {
     public sealed partial class HttpResponseHeaders : HttpHeaders
     {
-        private static readonly byte[] _CrLf = new[] { (byte)'\r', (byte)'\n' };
-        private static readonly byte[] _colonSpace = new[] { (byte)':', (byte)' ' };
+        private static ReadOnlySpan<byte> _CrLf => new[] { (byte)'\r', (byte)'\n' };
+        private static ReadOnlySpan<byte> _colonSpace => new[] { (byte)':', (byte)' ' };
 
         public Enumerator GetEnumerator()
         {

src/Servers/Kestrel/Core/src/Internal/Http2/Http2FrameWriter.cs

@@ -21,7 +21,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
     public class Http2FrameWriter
     {
         // Literal Header Field without Indexing - Indexed Name (Index 8 - :status)
-        private static readonly byte[] _continueBytes = new byte[] { 0x08, 0x03, (byte)'1', (byte)'0', (byte)'0' };
+        private static ReadOnlySpan<byte> _continueBytes => new byte[] { 0x08, 0x03, (byte)'1', (byte)'0', (byte)'0' };
 
         private readonly object _writeLock = new object();
         private readonly Http2Frame _outgoingFrame;