anchor.diff:          Http.AsyncRequestStream(url, ?query=query, ?headers=headers, ?httpMethod=httpMethod, ?body=body, ?cookies=cookies, ?cookieContainer=cookieContainer, 
                                   ?dontThrowOnHttpError=dontThrowOnHttpError, ?customizeHttpRequest=customizeHttpRequest, ?certificate=certificate)
   #endif
  -        |> Async.RunSynchronously+        |> Async.RunSynchronously
  
positive.code: #if FX_NO_WEBREQUEST_DATE
              | Date value -> req.Headers.[HeaderEnum.Date] <- value.ToString("R", CultureInfo.InvariantCulture)
  #else
              | Date value -> req.Date <- value
  #endif
  #if FX_NO_WEBREQUEST_EXPECT
              | Expect value -> req.Headers.[HeaderEnum.Expect] <- value.ToString(CultureInfo.InvariantCulture)
  
negative.code: #if FX_NO_WEBREQUEST_IFMODIFIEDSINCE
              | IfModifiedSince value -> req.Headers.[HeaderEnum.IfModifiedSince] <- value.ToString("R", CultureInfo.InvariantCulture)
  #else
              | IfModifiedSince value -> req.IfModifiedSince <- value.ToUniversalTime()
  #endif
              | IfNoneMatch value -> req.Headers.[HeaderEnum.IfNoneMatch] <- value
              | IfRange value -> req.Headers.[HeaderEnum.IfRange] <- value
  