load() {
    if (this.state !== TileState.IDLE && this.state !== TileState.ERROR) {
      return;
    }
    this.state = TileState.LOADING;
    this.changed();

    const self = this;
    this.loader_()
      .then(function (data) {
        self.data_ = data;
        self.state = TileState.LOADED;
        self.changed();
      })
      .catch(function (error) {
        self.error_ = error;
        self.state = TileState.ERROR;
        self.changed();
      });
  }
Load the tile data.
@api
@override