aspnetcore/samples/WebSocketSample/project.json

{
  "buildOptions": {
    "emitEntryPoint": true
  },

  "dependencies": {
    "Microsoft.NETCore.App": {
      "version": "1.2.0-*",
      "type": "platform"
    },
    "System.Net.WebSockets.Client": "4.3.0-*"
  },

  "frameworks": {
    "netcoreapp1.1": {}
  }
}