private Envelope[] filterExpired(IDocumentSession session, IEnumerable <Envelope> outgoing)
{
var expiredMessages = outgoing.Where(x => x.IsExpired()).ToArray();
_logger.DiscardedExpired(expiredMessages);
session.DeleteEnvelopes(_marker.Outgoing, expiredMessages);
return(outgoing.Where(x => !x.IsExpired()).ToArray());
}