% support for plotting num_points param

[baggiponte]

After #235 I could close #162 but I'd still like to keep the tabs open for supporting a % num_points param to display a % of the series.

[Graziano Montanaro]

Can I work on this? I might have a working solution, but it requires to collect the LazyFrame of the time series to get the row count. Is there a better way to do it staying lazy?

[baggiponte]

Sure! We are already collecting somewhere in the code (I'm on the phone so can't be super precise) so it should not be a huge problem.