withLaterDel method
Add query parameters to fetch messages deleted after the saved 'del' id
Implementation
MetaGetBuilder withLaterDel(int limit) {
// Specify 'since' only if we have already received some messages. If
// we have no locally cached messages then we don't care if any messages were deleted.
return withDel((topic.maxSeq > 0 ? topic.maxDel + 1 : null)!, limit);
}