"project": {
    // ...
    "restore": {
      // ...
      "configFilePaths": [
        "C:\\dev\\roslyn\\NuGet.config"
      ],
// ...

  "project": {
    // ...
    "restore": {
      // ...
      "configFilePaths": [
        "C:\\dev\\roslyn\\NuGet.Config",
        "C:\\Users\\sam\\AppData\\Roaming\\NuGet\\NuGet.Config",
        "C:\\Program Files (x86)\\NuGet\\Config\\Microsoft.VisualStudio.Offline.config"
      ],
// ...