Function compute_drb_result 

pub async fn compute_drb_result(
    drb_input: DrbInput,
    store_drb_progress: StoreDrbProgressFn,
    load_drb_progress: LoadDrbProgressFn,
    progress_load_timeout: Duration,
    heartbeat: Heartbeat,
    cancel: CancellationToken,
) -> Option<DrbResult>

Compute the DRB result for the leader rotation.

This is to be started two epochs in advance and spawned in a non-blocking thread. Returns None if the computation was cancelled via cancel.

Arguments

• drb_seed_input - Serialized QC signature.
• progress_load_timeout - Bound on the initial stored-progress load (see DRB_PROGRESS_LOAD_TIMEOUT).
• heartbeat - Bumped as the hash chain advances, so a supervisor can tell a long computation apart from a stalled one. Pass Heartbeat::default() when nobody is watching.
• cancel - Token that stops the hash loop when fired.