height/width from rc-resize-observer is strange in browser with low version

[sdhr27]

sample

in morden browser:

in 70.0.3538.77 chrome (or lower):

[sdhr27]

https://stackoverflow.com/questions/33636796/chrome-safari-not-filling-100-height-of-flex-parent/33644245#33644245
Turns out it's a classic flex bug in chrome and has nothing to do with rc-resize-observer.