Function should_take_over 

pub fn should_take_over(
    state: &TxnState,
    boot_only: bool,
    mine: bool,
    owner_alive: bool,
    now: Timestamp,
    deadline: Timestamp,
    renewed: Timestamp,
) -> bool

Whether the watchdog should take a transaction over (§12 recovery watchdog): only in the window where mutation may be under way, never from itself, and only when the owner is dead or has let both the transaction’s deadline and its lease’s grace period pass.