message: refactor(common): ensure empty StaticBufs don't make IoVecs
diff: @@ -23,11 +23,11 @@ impl Buf for StaticBuf {
  #[inline]
  fn bytes_vec<'t>(&'t self, dst: &mut [&'t IoVec]) -> usize {
  - if dst.is_empty() {
  - return 0;
  + if dst.is_empty() || self.0.is_empty() {
  + 0
  } else {
  dst[0] = self.0.into();
  - return 1;
  + 1
  }
  }
  }
  