pub fn set_details(&self, details: impl Serialize) {
        let details = serde_json::to_value(details).expect("failed serializing app details");
        let mut inner = self.inner.lock().expect("`AppHealthCheck` is poisoned");
        inner.app_details = Some(details);
    }
Sets app-level health details. They can include build info etc.
core/lib/health_check/src/lib.rs