Invoke what most subtle thing, so that region_highlight+=( ) is in effect

[Sebastian Gniazdowski <sgniazdowski@xxxxxxxxx>]

Hello,
I'm using zle -F to install handler to file descriptor obtained by <( ).

It seems to work very well, however I change region_highlight in the
handler, and the changes aren't rendered unless I call zle .redisplay
in the handler.

I'm worried that zle .redisplay is heavy, that it does too much and
can cause e.g. some blinking of command line, prompt.

So I decided to ask: does any other thing besides zle .redisplay have
the capability of making region_highlight in effect, rendered?

-- 
Best regards,
Sebastian Gniazdowski