Function run_consumer 

pub async fn run_consumer(
    ctx: Arc<LoadContext>,
    path: LoadPath,
    isolation: Isolation,
    tracker: Option<Arc<CommitTracker>>,
    consumer: Consumer,
    latencies: Latencies,
) -> Latencies

The live consumer group of path at isolation, until the load stops.

It measures create-time-to-poll latency for every record it polls, and, with a tracker, commits what it has polled every commit_interval and records each commit the coordinator acknowledged.