getTile(z, x, y, frameState) {
    const tile = this.getOrCreateTile(z, x, y, frameState);
    if (!tile) {
      return null;
    }
    return tile;
  }
@param {number} z Tile coordinate z.
@param {number} x Tile coordinate x.
@param {number} y Tile coordinate y.
@param {import("../../Map.js").FrameState} frameState Frame state.
@return {import("../../Tile.js").default|null} Tile (or null if outside source extent).
@protected