/// The length of time that you want a zonal shift to be active, which Route 53 ARC converts
/// to an expiry time (expiration time). Zonal shifts are temporary. You can set a zonal
/// shift to be active initially for up to three days (72 hours).If you want to still keep traffic away from an Availability Zone, you can update the
/// zonal shift and set a new expiration. You can also cancel a zonal shift, before it
/// expires, for example, if you're ready to restore traffic to the Availability Zone.To set a length of time for a zonal shift to be active, specify a whole number, and
/// then one of the following, with no space: <ul> <li> <p> <b>A lowercase letter m:</b>
/// To specify that the value is in minutes.</p> </li> <li> <p>
/// <b>A lowercase letter h:</b> To specify that the value is in hours.</p>
/// </li> </ul> <p>For example: <code>20h</code> means the
/// zonal shift expires in 20 hours. <code>120m</code> means the zonal shift
/// expires in 120 minutes (2 hours).</p>
///
///