Copied MessagePackHubProtocol files from https://github.com/dotnet/…

…aspnetcore/blob/0825def633c99d9fdd74e47e69bcde3935a5fe74/

sdk/signalr/Microsoft.Azure.WebJobs.Extensions.SignalRService/src/TriggerBindings/MessagePackHubProtocol/BinaryMessageFormatter.cs

@@ -0,0 +1,53 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Buffers;
+
+namespace Microsoft.AspNetCore.Internal;
+
+internal static class BinaryMessageFormatter
+{
+    public static void WriteLengthPrefix(long length, IBufferWriter<byte> output)
+    {
+        Span<byte> lenBuffer = stackalloc byte[5];
+
+        var lenNumBytes = WriteLengthPrefix(length, lenBuffer);
+
+        output.Write(lenBuffer.Slice(0, lenNumBytes));
+    }
+
+    public static int WriteLengthPrefix(long length, Span<byte> output)
+    {
+        // This code writes length prefix of the message as a VarInt. Read the comment in
+        // the BinaryMessageParser.TryParseMessage for details.
+        var lenNumBytes = 0;
+        do
+        {
+            ref var current = ref output[lenNumBytes];
+            current = (byte)(length & 0x7f);
+            length >>= 7;
+            if (length > 0)
+            {
+                current |= 0x80;
+            }
+            lenNumBytes++;
+        }
+        while (length > 0);
+
+        return lenNumBytes;
+    }
+
+    public static int LengthPrefixLength(long length)
+    {
+        var lenNumBytes = 0;
+        do
+        {
+            length >>= 7;
+            lenNumBytes++;
+        }
+        while (length > 0);
+
+        return lenNumBytes;
+    }
+}

sdk/signalr/Microsoft.Azure.WebJobs.Extensions.SignalRService/src/TriggerBindings/MessagePackHubProtocol/DefaultMessagePackHubProtocolWorker.cs

@@ -0,0 +1,36 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.IO;
+
+using MessagePack;
+
+namespace Microsoft.AspNetCore.SignalR.Protocol;
+
+internal sealed class DefaultMessagePackHubProtocolWorker : MessagePackHubProtocolWorker
+{
+    private readonly MessagePackSerializerOptions _messagePackSerializerOptions;
+
+    public DefaultMessagePackHubProtocolWorker(MessagePackSerializerOptions messagePackSerializerOptions)
+    {
+        _messagePackSerializerOptions = messagePackSerializerOptions;
+    }
+
+    protected override object? DeserializeObject(ref MessagePackReader reader, Type type, string field)
+    {
+        try
+        {
+            return MessagePackSerializer.Deserialize(type, ref reader, _messagePackSerializerOptions);
+        }
+        catch (Exception ex)
+        {
+            throw new InvalidDataException($"Deserializing object of the `{type.Name}` type for '{field}' failed.", ex);
+        }
+    }
+
+    protected override void Serialize(ref MessagePackWriter writer, Type type, object value)
+    {
+        MessagePackSerializer.Serialize(type, ref writer, value, _messagePackSerializerOptions);
+    }
+}