Firefox and Safari have onbufferedamountlow & bufferedAmountLowThreshold support (#3087)
Firefox and Safari have onbufferedamountlow & bufferedAmountLowThreshold support (#3087)

* ff, safari has onbufferedamountlow

* ff, safari have bufferedAmountLowThreshold

chrisdavidmills/browser-compat-data,mdn/browser-compat-data,mdn/browser-compat-data,chrisdavidmills/browser-compat-data