public static PersistentVMRole GetRole(this IServiceManagement proxy,
                                        string subscriptionId,
                                        string serviceName,
                                        string deploymentName,
                                        string roleName)
 {
     return((PersistentVMRole)proxy.EndGetRole(
                proxy.BeginGetRole(subscriptionId,
                                   serviceName,
                                   deploymentName,
                                   roleName,
                                   null,
                                   null)));
 }