Retrieving number of samples and time span of SampledPositionProperty

I have a very long Path (100,000 samples) that I’d like to animate. In order to improve performance I’m loading and unloading parts of the SampledPositionProperty as the timeline plays along.

In that context I’d like to have more insight on what’s in my SampledPositionProperty. I’d like to know how many samples are there at a given time, like a SampledPositionProperty.length properties. I’d also like to know what’s the duration my SampledPositionProperty spans across, may be SampledPositionProperty.availability holding a TimeInterval?

If alternative way to retrieves that information are already accessible, i’d be interested

Subsidiary question: what would be a safe number of samples (performance wise) to hold in memory at every given time?