Flann.fromDataset(dataset) become extremely slow when points equal 1000

[AndrewChan2022]

When I test web-examples\plane, build index is very fast when points number less than 1000, but quickly become very slow when points number is 1000.

var numberOfPivots = 999 is very fast. less than 1 seconds.

var numberOfPivots = 1000 extremly slow. about 10 seconds.