Function later_full 

fn later_full(
    sharing: &Sharing<'_>,
    computer: &str,
    rounds: &[u32],
    round: u32,
) -> Option<u32>

The first of another computer’s rounds after round that opens full (Turn): it restates all that computer held, so a reader waiting for the end of an earlier round, which may never come (an older copy of it put back), reads on from there. Each round’s first line read alone.