function EntityCluster(options) {
  options = options ?? Frozen.EMPTY_OBJECT;

  this._enabled = options.enabled ?? false;
  this._pixelRange = options.pixelRange ?? 80;
  this._minimumClusterSize = options.minimumClusterSize ?? 2;
  this._clusterBillboards = options.clusterBillboards ?? true;
  this._clusterLabels = options.clusterLabels ?? true;
  this._clusterPoints = options.clusterPoints ?? true;

  this._labelCollection = undefined;
  this._billboardCollection = undefined;
  this._pointCollection = undefined;

  this._clusterBillboardCollection = undefined;
  this._clusterLabelCollection = undefined;
  this._clusterPointCollection = undefined;

  this._collectionIndicesByEntity = {};

  this._unusedLabelIndices = [];
  this._unusedBillboardIndices = [];
  this._unusedPointIndices = [];

  this._previousClusters = [];
  this._previousHeight = undefined;

  this._enabledDirty = false;
  this._clusterDirty = false;

  this._cluster = undefined;
  this._removeEventListener = undefined;

  this._clusterEvent = new Event();

  /**
   * Determines if entities in this collection will be shown.
   *
   * @type {boolean}
   * @default true
   */
  this.show = options.show ?? true;
}
Defines how screen space objects (billboards, points, labels) are clustered.

@param {object} [options] An object with the following properties:
@param {boolean} [options.enabled=false] Whether or not to enable clustering.
@param {number} [options.pixelRange=80] The pixel range to extend the screen space bounding box.
@param {number} [options.minimumClusterSize=2] The minimum number of screen space objects that can be clustered.
@param {boolean} [options.clusterBillboards=true] Whether or not to cluster the billboards of an entity.
@param {boolean} [options.clusterLabels=true] Whether or not to cluster the labels of an entity.
@param {boolean} [options.clusterPoints=true] Whether or not to cluster the points of an entity.
@param {boolean} [options.show=true] Determines if the entities in the cluster will be shown.

@alias EntityCluster
@constructor

@demo {@link https://sandcastle.cesium.com/index.html?src=Clustering.html|Cesium Sandcastle Clustering Demo}