+ $cb->([$mime, 0, 1], $cb_arg);
+ }
+}
+
+# Use this when we may accept Email::MIME from user scripts
+# (not just PublicInbox::MIME)
+sub msg_iter ($$;$$) { # $_[0] = PublicInbox::MIME/Email::MIME-like obj
+ my (undef, $cb, $cb_arg, $once) = @_;
+ if (my $ep = $_[0]->can('each_part')) { # PublicInbox::{MIME,*}
+ $ep->($_[0], $cb, $cb_arg, $once);
+ } else { # for compatibility with existing Email::MIME users:
+ em_each_part($_[0], $cb, $cb_arg, $once);