pub const HISTORY_CAP: usize = 20;Expand description
How many of a row’s own transitions a board row carries.
The newest this many, at a measured ~250 bytes per transition - so a
capped row weighs ~5 KiB and a row has to move more than twenty times
before anything is withheld. The whole count rides beside the tail in
history_total, so what the cap withholds is stated rather than silent.