message: Comment about how we print downloads
diff: @@ -481,9 +481,25 @@ impl<'a, 'cfg> Downloads<'a, 'cfg> {
  self.enqueue(dl, handle)?;
  };
  self.pending_ids.remove(&dl.id);
  +
  + // If the progress bar isn't enabled then we still want to provide some
  + // semblance of progress of how we're downloading crates. Historically
  + // we did this by printing `Downloading ...` as we downloaded each crate
  + // one at a time, but now we download them all in parallel so there's no
  + // sense of progress if they get printed all at once.
  + //
  + // As a sort of weird compromise/hack we print `Downloading ...` when a
  + // crate is *finished* rather than when it starts. This should give a
  + // good sense of progress as we're printing as things complete (as
  + // opposed to all at once at the beginning). It's a bit of a lie because
  + // the crate is already downloaded, though.
  + //
  + // We can continue to iterate on this, but this is hopefully good enough
  + // for now.
  if !self.progress.borrow().is_enabled() {
  self.set.config.shell().status("Downloading", &dl.descriptor)?;
  }
  +
  self.downloads_finished += 1;
  self.downloaded_bytes += dl.total.get();
  self.tick(true)?;
  