Constant UNKNOWN_TURN 

const UNKNOWN_TURN: u64 = u64::MAX; // 18_446_744_073_709_551_615u64

The turn of a round that does not know where the round before it ended (Turn::p): one that could not restate all (new_round) after a round of its own found without a line. No reader ever met that line: it waits for the round before as for a lost one (AWAITED), then reads on with the gap said, the doses in doubt until a full round, never as an older Sioul’s round, which would take all before it as read.