perf how

1.   minimum free time between digest cycles - allows HTML and CSS to process - perf  ===   50-100 is required
2.   n digest cycles per sec - digest rate
3.   group digest cycles for digest debounce time - shows continuous max n digest involvement - can be huge perf effect
4.   show digest group
5.   watchers group by exp with time
6.   ngIf, ngClass, ngStyle, ngShow, ngRepeat - perf effect
7.   browser event involvement in digest group
8.   directive perf effect
9.   create views without affecting actual data - clone data and process
10.  so many watches can cause perf issues
11.  expensive watches - causing dom time, or big digest group
12.  create observers





Highlights Digest :

digest rate :  n fps
longest: ms
avg : ms
allowed longest dom time:  ms
dom update rate: fps