System.Net.Http.WinHttpException.CreateExceptionUsingError C# (CSharp) Method

        public static WinHttpException CreateExceptionUsingError(int error)
        {
            return new WinHttpException(error, GetErrorMessage(error));
        }

        public WinInetProxyHelper()
        {
            var proxyConfig = new Interop.WinHttp.WINHTTP_CURRENT_USER_IE_PROXY_CONFIG();

            try
            {
                if (Interop.WinHttp.WinHttpGetIEProxyConfigForCurrentUser(out proxyConfig))
                {
                    AutoConfigUrl = Marshal.PtrToStringUni(proxyConfig.AutoConfigUrl);
                    AutoDetect    = proxyConfig.AutoDetect;
                    Proxy         = Marshal.PtrToStringUni(proxyConfig.Proxy);
                    ProxyBypass   = Marshal.PtrToStringUni(proxyConfig.ProxyBypass);
                }
                else
                {
                    var lastError = Marshal.GetLastWin32Error();
                    if (lastError != Interop.WinHttp.ERROR_FILE_NOT_FOUND)
                    {
                        throw WinHttpException.CreateExceptionUsingError(lastError);
                    }
                }
            }
            finally
            {
                // FreeHGlobal already checks for null pointer before freeing the memory.
                Marshal.FreeHGlobal(proxyConfig.AutoConfigUrl);
                Marshal.FreeHGlobal(proxyConfig.Proxy);
                Marshal.FreeHGlobal(proxyConfig.ProxyBypass);
            }
        }