remove redundant code unit size check
remove redundant code unit size check

kawanet/buffer,SAGV/buffer,kawanet/buffer,SAGV/buffer,btd/buffer,feross/buffer,loon3/buffer,LinusU/buffer,beni55/buffer,beni55/buffer,LiuDeng/buffer,feross/buffer,feross/buffer,LinusU/buffer,loon3/buffer,btd/buffer,nolanlawson/buffer,nolanlawson/buffer,LiuDeng/buffer