Stop UTF8 decoding/reencoding in Fortunes platform

src/BenchmarksApps/TechEmpower/PlatformBenchmarks/BenchmarkApplication.Fortunes.cs

@@ -1,7 +1,9 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.IO.Pipelines;
 using System.Text.Encodings.Web;
 using System.Threading.Tasks;
@@ -43,6 +45,37 @@ private void OutputFortunes(PipeWriter pipeWriter, List<Fortune> model)
             // Date header
             writer.Write(DateHeader.HeaderBytes);
 
+            var bodyStart = writer.Buffered;
+            // Body
+            writer.Write(_fortunesTableStart);
+            foreach (var item in model)
+            {
+                writer.Write(_fortunesRowStart);
+                writer.WriteNumeric((uint)item.Id);
+                writer.Write(_fortunesColumn);
+                HtmlEncoder.EncodeUtf8(item.Message.AsSpan(), writer.Span, out var bytesConsumed, out var bytesWritten, isFinalBlock: true);
+                Debug.Assert(bytesConsumed == item.Message.Length, "Not enough remaining space in the buffer");
+                writer.Advance(bytesWritten);
+                writer.Write(_fortunesRowEnd);
+            }
+            writer.Write(_fortunesTableEnd);
+            lengthWriter.WriteNumeric((uint)(writer.Buffered - bodyStart));
+
+            writer.Commit();
+        }
+
+        private void OutputFortunes(PipeWriter pipeWriter, List<FortuneDapper> model)
+        {
+            var writer = GetWriter(pipeWriter, sizeHint: 1600); // in reality it's 1361
+
+            writer.Write(_fortunesPreamble);
+
+            var lengthWriter = writer;
+            writer.Write(_contentLengthGap);
+
+            // Date header
+            writer.Write(DateHeader.HeaderBytes);
+
             var bodyStart = writer.Buffered;
             // Body
             writer.Write(_fortunesTableStart);

src/BenchmarksApps/TechEmpower/PlatformBenchmarks/BufferWriter.cs

@@ -45,7 +45,7 @@ public void Advance(int count)
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public void Write(ReadOnlySpan<byte> source)
+        public void Write(scoped ReadOnlySpan<byte> source)
         {
             if (_span.Length >= source.Length)
             {
@@ -78,7 +78,7 @@ private void EnsureMore(int count = 0)
             _span = _output.GetSpan(count);
         }
 
-        private void WriteMultiBuffer(ReadOnlySpan<byte> source)
+        private void WriteMultiBuffer(scoped ReadOnlySpan<byte> source)
         {
             while (source.Length > 0)
             {

src/BenchmarksApps/TechEmpower/PlatformBenchmarks/Data/DapperDb.cs

@@ -13,20 +13,20 @@ public class DapperDb
         public DapperDb(AppSettings appSettings)
             => _connectionString = appSettings.ConnectionString;
 
-        public async Task<List<Fortune>> LoadFortunesRows()
+        public async Task<List<FortuneDapper>> LoadFortunesRows()
         {
-            List<Fortune> result;
+            List<FortuneDapper> result;
 
             using (var db = new NpgsqlConnection(_connectionString))
             {
                 // Note: don't need to open connection if only doing one thing; let dapper do it
-                result = (await db.QueryAsync<Fortune>("SELECT id, message FROM fortune")).AsList();
+                result = (await db.QueryAsync<FortuneDapper>("SELECT id, message FROM fortune")).AsList();
             }
 
-            result.Add(new Fortune(id: 0, message: "Additional fortune added at request time." ));
+            result.Add(new FortuneDapper(id: 0, message: "Additional fortune added at request time." ));
             result.Sort();
 
             return result;
         }
     }
-}
+}

src/BenchmarksApps/TechEmpower/PlatformBenchmarks/Data/Fortune.cs

@@ -1,25 +1,25 @@
-// Copyright (c) .NET Foundation. All rights reserved. 
-// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information. 
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
 
 namespace PlatformBenchmarks
 {
     public readonly struct Fortune : IComparable<Fortune>, IComparable
     {
-        public Fortune(int id, string message)
+        public Fortune(int id, byte[] message)
         {
             Id = id;
             Message = message;
         }
 
         public int Id { get; }
 
-        public string Message { get; }
+        public byte[] Message { get; }
 
         public int CompareTo(object obj) => throw new InvalidOperationException("The non-generic CompareTo should not be used");
 
         // Performance critical, using culture insensitive comparison
-        public int CompareTo(Fortune other) => string.CompareOrdinal(Message, other.Message);
+        public int CompareTo(Fortune other) => Message.AsSpan().SequenceCompareTo(other.Message.AsSpan());
     }
 }

src/BenchmarksApps/TechEmpower/PlatformBenchmarks/Data/FortuneDapper.cs

@@ -0,0 +1,25 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+
+namespace PlatformBenchmarks
+{
+    public readonly struct FortuneDapper : IComparable<FortuneDapper>, IComparable
+    {
+        public FortuneDapper(int id, string message)
+        {
+            Id = id;
+            Message = message;
+        }
+
+        public int Id { get; }
+
+        public string Message { get; }
+
+        public int CompareTo(object obj) => throw new InvalidOperationException("The non-generic CompareTo should not be used");
+
+        // Performance critical, using culture insensitive comparison
+        public int CompareTo(FortuneDapper other) => string.CompareOrdinal(Message, other.Message);
+    }
+}

src/BenchmarksApps/TechEmpower/PlatformBenchmarks/Data/FortuneEf.cs

@@ -17,14 +17,7 @@ public class FortuneEf : IComparable<FortuneEf>, IComparable
         [Required]
         public string Message { get; set; }
 
-        public int CompareTo(object obj)
-        {
-            return CompareTo((FortuneEf)obj);
-        }
-
-        public int CompareTo(FortuneEf other)
-        {
-            return String.CompareOrdinal(Message, other.Message);
-        }
+        public int CompareTo(object obj) => CompareTo((FortuneEf)obj);
+        public int CompareTo(FortuneEf other) => String.CompareOrdinal(Message, other.Message);
     }
-}
+}

src/BenchmarksApps/TechEmpower/PlatformBenchmarks/Data/RawDb.cs

@@ -255,17 +255,19 @@ public async Task<List<Fortune>> LoadFortunesRows()
                     result.Add(new Fortune
                     (
                         id: rdr.GetInt32(0),
-                        message: rdr.GetString(1)
+                        message: rdr.GetFieldValue<byte[]>(1)
                     ));
                 }
             }
 
-            result.Add(new Fortune(id: 0, message: "Additional fortune added at request time." ));
+            result.Add(new Fortune(id: 0, AdditionalFortune));
             result.Sort();
 
             return result;
         }
 
+        private readonly byte[] AdditionalFortune = "Additional fortune added at request time."u8.ToArray();
+
         private (NpgsqlCommand readCmd, NpgsqlParameter<int> idParameter) CreateReadCommand(NpgsqlConnection connection)
         {
 #if NET6_0_OR_GREATER