anchor.diff:        [<JsonProperty("packageContent")>]
         DownloadLink: string
         [<JsonProperty("catalogEntry")>]
  -      PackageDetails: Catalog
  -      }
  +      PackageDetails: Catalog }
   
   type PackageIndexPage =
       { [<JsonProperty("@id")>]
  
positive.code:                 return
                      match v3res with
                      | Choice1Of2 s -> Some s
                      | Choice2Of2 ex -> 
                          if verbose then traceWarnfn "getAllVersionsAPI: %s" (ex.ToString())
                          None
          } |> Async.StartAsTask)
  
negative.code: let private allVersionsDict = new System.Collections.Concurrent.ConcurrentDictionary<_,System.Threading.Tasks.Task<_>>()
  
  /// Calculates the NuGet v3 URL from a NuGet v2 URL.
  let calculateNuGet3Path(nugetUrl:string) =
      match nugetUrl.TrimEnd([|'/'|]) with
      | "http://nuget.org/api/v2" -> Some "http://api.nuget.org/v3/index.json"
      | "https://nuget.org/api/v2" -> Some "https://api.nuget.org/v3/index.json"
  