public static void DeleteRole(this IServiceManagement proxy,
                               string subscriptionId,
                               string serviceName,
                               string deploymentName,
                               string roleName)
 {
     proxy.EndDeleteRole(
         proxy.BeginDeleteRole(subscriptionId,
                               serviceName,
                               deploymentName,
                               roleName,
                               null,
                               null));
 }