cleanup

Author: BrennanConroy

src/SignalR/clients/csharp/Http.Connections.Client/src/HttpConnection.cs

@@ -7,7 +7,6 @@
 using System.Linq;
 using System.Net.Http;
 using System.Net.WebSockets;
-using System.Runtime.InteropServices;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Connections;
@@ -30,9 +29,6 @@ public partial class HttpConnection : ConnectionContext, IConnectionInherentKeep
         private static readonly Task<string> _noAccessToken = Task.FromResult<string>(null);
 
         private static readonly TimeSpan HttpClientTimeout = TimeSpan.FromSeconds(120);
-#if !NETCOREAPP3_0
-        private static readonly Version Windows8Version = new Version(6, 2);
-#endif
 
         private readonly ILogger _logger;