// volumeHandle is the unique volume name returned by the CSI volume
  // plugin’s CreateVolume to refer to the volume on all subsequent calls.
  // Required.
  optional string volumeHandle = 2;

  // readOnly value to pass to ControllerPublishVolumeRequest.
  // Defaults to false (read/write).
  // +optional
  optional bool readOnly = 3;

  // fsType to mount. Must be a filesystem type supported by the host operating system.