Followed

A batch a follow has just produced.

reachesStart is true only on the batch a follow opens with, and only when that batch reached the session's beginning — the same fact EntryPage.older carries for a page a reader asks for once. Everything a transcript grows by afterwards says false, because growth is never a beginning.

A follow that re-subscribes — the file was not written yet, the connection was re-made — opens again, so the fact arrives again with the batch it belongs to rather than being remembered anywhere.