Function metrics_settings 

pub fn metrics_settings(config: &PipelineConfig) -> MetricsSettings

The MetricsSettings a pipeline configuration maps to.

Assemblies that pre-register metric handles (sink shard metrics, custom metrics) should call metrics::install(&metrics_settings(&config)) before constructing them; the runtime’s own install then reuses the exporter. Handles built before any install bind to the no-op recorder and render nothing.