Function construct 

pub(super) fn construct<G: Scope<Timestamp = Timestamp>>(
    scope: G,
    config: &LoggingConfig,
    metrics_registry: MetricsRegistry,
    now: Instant,
    start_offset: Duration,
    worker_config: Rc<ConfigSet>,
    workers_per_process: usize,
) -> Return

Constructs the logging dataflow fragment for Prometheus metrics.