readPolygon() {
    const numRings = this.readUint32();

    /** @type {Array<Array<import('../coordinate.js').Coordinate>>} */
    const rings = [];
    for (let i = 0; i < numRings; i++) {
      rings.push(this.readLineString()); // as a LinearRing
    }

    return rings;
  }
@return {Array<Array<import('../coordinate.js').Coordinate>>} coords for Polygon like