Probably a plugin time delay effect of some sort. It's sunday so my brain hasn't kicked into gear yet to think of a particular one
You could replicate it by either drawing in the notes from 16ths right up 64's like a drum roll to get it close. Or you could try linking an LFO with saw wave to trigger the notes and use the LFO rate to mimic it. If using either technique just add a little bit of pitch bend to lift the notes up