aspnetcore/src/Connections.Abstractions/ConnectionContext.cs

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

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

        public abstract IFeatureCollection Features { get; }

        public abstract IDictionary<object, object> Items { get; set; }

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