// medium represents what type of storage medium should back this directory.
  // The default is "" which means to use the node's default medium.
  // Must be an empty string (default) or Memory.
  // More info: https://kubernetes.io/docs/concepts/storage/volumes#emptydir
  // +optional
  optional string medium = 1;

  // sizeLimit is the total amount of local storage required for this EmptyDir volume.