Function resolve_driver_name 

pub fn resolve_driver_name(
    adapter: &str,
    selector_param: &str,
    params: &HashMap<String, String>,
) -> Option<&'static str>

Resolve the driver name for an (adapter, params) pair without instantiating anything. Used by the resource pool’s Push B path: the executor needs the resolved driver name to look up a SharedDriverRegistration before deciding which attach path to use. Mirrors the resolution logic in instantiate_with_driver — user-supplied selector first (comma-separated, in order), then the rank-sorted default list.

Returns DEFAULT_DRIVER_NAME when no DriverImpl is registered for the adapter (single-engine adapters that only register via AdapterRegistration). Single-engine adapters that opt into pool sharing submit their SharedDriverRegistration with the same sentinel.