Apply API Review feedback to JsonHubProtocolOptions

[BrennanConroy]

Specifically, we should review the JsonHubProtocolOptions for the new System.Text.Json based protocol.

[analogrelay]

Let's do a brief online API review. @BrennanConroy post the ref assembly code here when you've locked it down. We can probably approve this without a meeting.

[BrennanConroy]

Current API

namespace Microsoft.AspNetCore.SignalR
{
    public partial class JsonHubProtocolOptions
    {
        public JsonHubProtocolOptions() { }
        public System.Text.Json.Serialization.JsonSerializerOptions PayloadSerializerOptions { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute]set { } }
    }
}
namespace Microsoft.AspNetCore.SignalR.Protocol
{
    public sealed partial class JsonHubProtocol : Microsoft.AspNetCore.SignalR.Protocol.IHubProtocol
    {
        public JsonHubProtocol() { }
        public JsonHubProtocol(Microsoft.Extensions.Options.IOptions<Microsoft.AspNetCore.SignalR.JsonHubProtocolOptions> options) { }
        public string Name { get { throw null; } }
        public Microsoft.AspNetCore.Connections.TransferFormat TransferFormat { get { throw null; } }
        public int Version { get { throw null; } }
        public System.ReadOnlyMemory<byte> GetMessageBytes(Microsoft.AspNetCore.SignalR.Protocol.HubMessage message) { throw null; }
        public bool IsVersionSupported(int version) { throw null; }
        public bool TryParseMessage(ref System.Buffers.ReadOnlySequence<byte> input, Microsoft.AspNetCore.SignalR.IInvocationBinder binder, out Microsoft.AspNetCore.SignalR.Protocol.HubMessage message) { throw null; }
        public void WriteMessage(Microsoft.AspNetCore.SignalR.Protocol.HubMessage message, System.Buffers.IBufferWriter<byte> output) { }
    }
}
namespace Microsoft.Extensions.DependencyInjection
{
    public static partial class JsonProtocolDependencyInjectionExtensions
    {
        public static TBuilder AddJsonProtocol<TBuilder>(this TBuilder builder) where TBuilder : Microsoft.AspNetCore.SignalR.ISignalRBuilder { throw null; }
        public static TBuilder AddJsonProtocol<TBuilder>(this TBuilder builder, System.Action<Microsoft.AspNetCore.SignalR.JsonHubProtocolOptions> configure) where TBuilder : Microsoft.AspNetCore.SignalR.ISignalRBuilder { throw null; }
    }
}

Semi-related to API are our default Json options, currently we have:

options.WriteIndented = false;
options.ReadCommentHandling = JsonCommentHandling.Disallow;
options.AllowTrailingCommas = false;
options.IgnoreNullValues = false;
options.IgnoreReadOnlyProperties = false;
options.PropertyNamingPolicy = JsonNamingPolicy.CamelCase;

There are a couple other settable options right now, do we want to set them or just keep the defaults?:

DefaultBufferSize = 16 * 1024;
DictionaryKeyPolicy = null;
MaxDepth = 0; // meaning 64
PropertyNameCaseInsensitive = false;

@davidfowl @mikaelm12 @halter73 @anurse

[analogrelay]

All the methods/properties on JsonHubProtocol (except the constructors) are just the ones that come from IHubProtocol right? So they're not really negotiable anyway :)

Given that, I think we're in a good place. Now that we can just expose the JsonSerializerOptions type, we basically have the same API and the Newtonsoft.Json one.

[halter73]

MaxDepth = 0; // meaning 64 Why not just make it 64 then?

[BrennanConroy]

Those are the defaults set by new JsonSerializerOptions(); I'm not setting 0 or 64. The ask is do we want to set these, or keep the defaults?