message: Use SmallVec instead of Vec for echo builtin
diff: use std::io::{self, BufWriter, Write};
  +use smallvec::SmallVec;
  bitflags! {
  struct Flags : u8 {
  @@ -10,7 +11,7 @@ bitflags! {
  pub(crate) fn echo(args: &[&str]) -> Result<(), io::Error> {
  let mut flags = Flags::empty();
  - let mut data: Vec<&str> = vec![];
  + let mut data: SmallVec<[&str; 16]> = SmallVec::with_capacity(16);
  for arg in args {
  match *arg {
  