applyTransform(transformFn) {
    transformFn(this.flatCoordinates_, this.flatCoordinates_, this.stride_);
  }
Apply a transform function to the coordinates of the geometry.
The geometry is modified in place.
If you do not want the geometry modified in place, first `clone()` it and
then use this function on the clone.
@param {import("../proj.js").TransformFunction} transformFn Transform function.