Function background_on_demand_acme_task 

pub async fn background_on_demand_acme_task(
    existing_combinations: HashSet<(String, u16)>,
    acme_on_demand_rx: Receiver<(String, u16)>,
    on_demand_tls_ask_endpoint: Option<Uri>,
    on_demand_tls_ask_endpoint_verify: bool,
    acme_logger: Arc<ErrorLogger>,
    crypto_provider: Arc<CryptoProvider>,
    acme_configs_mutex: Arc<Mutex<Vec<AcmeConfig>>>,
    acme_on_demand_configs: Vec<AcmeOnDemandConfig>,
    memory_acme_account_cache_data: Arc<RwLock<HashMap<String, Vec<u8>>>>,
    prevent_file_race_conditions_sem: Arc<Semaphore>,
)

Performs background automatic TLS on demand tasks.