code: function ListCollectionIdsRequest(properties) {
                      if (properties)
                          for (var keys = Object.keys(properties), i = 0; i < keys.length; ++i)
                              if (properties[keys[i]] != null)
                                  this[keys[i]] = properties[keys[i]];
                  }
docs: Properties of a ListCollectionIdsRequest.
  @memberof google.firestore.v1
  @interface IListCollectionIdsRequest
  @property {string|null} [parent] ListCollectionIdsRequest parent
  @property {number|null} [pageSize] ListCollectionIdsRequest pageSize
  @property {string|null} [pageToken] ListCollectionIdsRequest pageToken
   
  Constructs a new ListCollectionIdsRequest.
  @memberof google.firestore.v1
  @classdesc Represents a ListCollectionIdsRequest.
  @implements IListCollectionIdsRequest
  @constructor
  @param {google.firestore.v1.IListCollectionIdsRequest=} [properties] Properties to set