Keep up with upstream Rust: RingBuf -> VecDeque
Keep up with upstream Rust: RingBuf -> VecDeque

RingBuf was renamed as per https://github.com/rust-lang/rfcs/pull/580

stepancheg/solicit,gwicke/solicit,jinnjuice/solicit,tempbottle/solicit,mlalic/solicit,Galvanization/solicit