message: Document design choice to use temporary directory
diff: @@ -234,6 +234,10 @@ impl Session {
  }
  }
  Action::DumpQueues => {
  + // Note: The preferable approach would be to use a tempfile instead of a
  + // named one in a temporary directory, and return it through the
  + // responder. This is currently hamstrung since `bincode` does not
  + // allow retrieving the inner writer from its serializer.
  let tempdir = tempfile::tempdir().expect("FIXME");
  let tempfile_path = tempdir.path().join("queue-dump");
  