aspnetcore/src/Protocols.Abstractions/ConnectionContext.cs

using System.IO.Pipelines;
using Microsoft.AspNetCore.Http.Features;

namespace Microsoft.AspNetCore.Protocols
{
    public abstract class ConnectionContext
    {
        public abstract string ConnectionId { get; set; }

        public abstract IFeatureCollection Features { get; }

        public abstract IDuplexPipe Transport { get; set; }
    }
}