Wait for an event, but return a copy so we can investigate parameters.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 1478553214-497-3-git-send-email-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>