Formatting is much faster than before, but still terribly slow compared to simply rounding numbers using math and floor and ceiling appropriately. Ryu is more

Formatting is much faster than before, but still terribly slow compared to simply rounding numbers using math and floor and ceiling appropriately. Ryu is more than 100x slower than something like rval = floor(100*val+0.5)/100.0 (which is not quite right due to numerical issues, but close, and illustrates the idea). Formatting, to get a rounded float, is terribly slow.