Function massa_bootstrap::client::check_restart_metadata

fn check_restart_metadata(
    cfg: &BootstrapConfig,
    last_start_period: &Option<u64>,
    last_slot_before_downtime: &Option<Option<Slot>>,
) -> Result<(), BootstrapError>

Checks the network restart metadata announced by a bootstrap server.

The server sends last_start_period and last_slot_before_downtime together, and only once per stream (on the first part, before any consensus blocks). Startup derives the network downtime range and its timestamps from them (see massa-node), assuming they describe a coherent interval, so anything else has to be rejected as a bootstrap failure rather than stored.