message: nydus-image: update comments for PostWalkAction::Break
diff: @@ -922,8 +922,8 @@ impl RafsInode for OndiskInodeWrapper {
  trace!("found file {:?}, nid {}", name, nid);
  cur_offset += 1;
  match handler(Some(inode), name.to_os_string(), nid, cur_offset) {
  - // The PostWalkAction::Break indicates that the entire process needs to end,
  - // so return is required here, because this is a nested loop,
  + // Break returned by handler indicates that there is not enough buffer of readdir for entries inreaddir,
  + // such that it has to return. because this is a nested loop,
  // using break can only jump out of the internal loop, there is no way to jump out of the whole loop.
  Ok(PostWalkAction::Break) => return Ok(()),
  Ok(PostWalkAction::Continue) => continue,
  