private static void AddAuthenticationToRequest(IWebClient webClient, Jira jira)
        {
            var credentials = jira.GetCredentials();

            if (String.IsNullOrEmpty(credentials.UserName) || String.IsNullOrEmpty(credentials.Password))
            {
                throw new InvalidOperationException("Unable to download attachment, user and/or password are missing. You can specify a provider for credentials when constructing the Jira instance.");
            }

            webClient.AddQueryString("os_username", Uri.EscapeDataString(credentials.UserName));
            webClient.AddQueryString("os_password", Uri.EscapeDataString(credentials.Password));
        }