That's so cool! I always felt the problem when an uphill section comes, the lag is so bad that until the hub locks I am already past the section and already going back downhill.
Sometimes my sprints come back to haunt my in my dreams, so bad is the lag.
My bullshit detector had absolutely zero lag when I started reading this
https://www.kickstarter.com/projects/2096335262/zhero-rear-bicycle-hub-zero-lag
From the description, it seems that they want AU$155,000 to start making Shimano Silent Clutch freehubs