Signals upon Dash showing/hiding

[Ivan Sagalaev]

Hello everyone,

I'm looking into ways to speed up generation of search results in my 
Unity lens. One thing I could do is to cache some intermediate data to 
avoid searching everything from scratch on every new letter entered by a 
user. Such a cache has to be invalidated somehow and one thing that 
could trigger it is the event of showing (or hiding) of the Dash (I can 
safely assume for my lens that results for any given search query won't 
change while the Dash is active).

So my questions is: are there any such signals that I could hook onto? 
The Dash showing/hiding? A scope "activated" for a new search? May be 
something else?

Thanks!