Guarantee vec.clear/truncate is O(1) for trivial types
Guarantee vec.clear/truncate is O(1) for trivial types

graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust