fn just_below(ts: &str) -> StringExpand description
The exclusive read position just below ts.
A thread’s cursor is exclusive, so seeding one from a reply would skip that reply - the reply is usually the news that brought the thread in. Seeding it from the parent instead would skip nothing, but a parent can be weeks old, and the idle window reads the cursor: the thread would be dropped before its first walk. One microsecond below the newest reply is both recent and below everything still worth delivering.