Is it safe to use the combine-after-change-calls like this?

[Zhang Haijun]

I want to use it with 
multiple-cursors.el(https://github.com/magnars/multiple-cursors.el) like this:
1. When multiple-cursors activates, set combine-after-change-calls to t
2. Edit the buffer with multiple active cursors
3. Before multiple-cursors deactivates, call combine-after-change-execute and 
set combine-after-change-calls back to nil.

I’m using the package iedit.el(https://github.com/victorhge/iedit). It works 
like multiple-cursors.el, which has multiple active cursors.  

The problem is that: when editing with multiple active cursors, emacs lags too 
much. It seems that most of cpu is used by functions in after-change-functions.

The issue: https://github.com/victorhge/iedit/issues/83