function FeatureIdAttribute() {
  /**
   * How many unique features are defined in this set of feature IDs
   *
   * @type {number}
   * @private
   */
  this.featureCount = undefined;

  /**
   * This value indicates that no feature is indicated with this vertex
   *
   * @type {number}
   * @private
   */
  this.nullFeatureId = undefined;

  /**
   * The ID of the property table that feature IDs index into. If undefined,
   * feature IDs are used for classification, but no metadata is associated.
   *
   *
   * @type {number}
   * @private
   */
  this.propertyTableId = undefined;

  /**
   * The set index of feature ID attribute containing feature IDs.
   *
   * @type {number}
   * @private
   */
  this.setIndex = undefined;

  /**
   * The label to identify this set of feature IDs. This is used in picking,
   * styling and shaders.
   *
   * @type {string}
   * @private
   */
  this.label = undefined;

  /**
   * Label to identify this set of feature IDs by its position in the array.
   * This will always be either "featureId_N" for primitives or
   * "instanceFeatureId_N" for instances.
   *
   * @type {string}
   * @private
   */
  this.positionalLabel = undefined;
}
Maps per-vertex or per-instance feature IDs to a property table. Feature
IDs are stored in an accessor.

@alias ModelComponents.FeatureIdAttribute
@constructor

@private