openlayers/ol3 — pull request #3013 by gberaudo (2014-12-05 14:43:30+00:00)
Title: Improve vector source clear() performance

Speeds up from 8 seconds to 350ms the clearing of 100'000 features.

This 24 times improvement is in part gained by dispatching a single `clear` event in spite of sending a `removefeature` event for each of the 100'000` features.