// If not set to true, the field can be modified at any time.
  // Defaulted to nil.
  // +optional
  optional bool immutable = 4;

  // Data contains the configuration data.
  // Each key must consist of alphanumeric characters, '-', '_' or '.'.
  // Values with non-UTF-8 byte sequences must use the BinaryData field.
  // The keys stored in Data must not overlap with the keys in