Swift Error: '%' is unavailable, use truncatingRemainder instead

Swift3之后，非整数求余，不能再用%

let rem = 2.5.truncatingRemainder(dividingBy: 1.1)
print(rem) // 0.3

原文：https://stackoverflow.com/questions/40495301/what-does-is-unavailable-use-truncatingremainder-instead-mean