Function init_with_provider 

pub fn init_with_provider(
    exporter: PrometheusExporter,
    provider: SdkMeterProvider,
) -> bool

Initializes the global metric state with the given exporter and provider.

This must be called before any metric is created if you want all instruments to feed into a custom provider (e.g. one that also has an OTLP reader).

Returns false if the state was already initialized.