Is `getMinIntrinsicWidth` really that expensive?

In the Flutter documentation, I read:

abstract class RenderBox extends RenderObject {
...

  /// Calling this function is expensive as it can result in O(N^2) behavior.
  ...
  double getMinIntrinsicWidth(double height) {

I was unable to find more information about when and why this is so expensive and even what N means in the big O. Height (), number of widgets, depth of tree, number of calls, ...?

Has someone an example with O(N^2) runtime?