getTileInternal(z, x, y, pixelRatio, projection) {
    const key = this.getKey();
    return this.createTile_(z, x, y, pixelRatio, projection, key);
  }
@param {number} z Tile coordinate z.
@param {number} x Tile coordinate x.
@param {number} y Tile coordinate y.
@param {number} pixelRatio Pixel ratio.
@param {!import("../proj/Projection.js").default} projection Projection.
@return {!ImageTile} Tile.
@protected