Function check_provider 

pub async fn check_provider(
    storage: &StorageConnection<impl ProviderOps + ?Sized>,
    path: &ObjectPath,
    encrypted_bytes: &[u8],
) -> Result<(), StorageCheckError>

Check a candidate provider before reserving or publishing setup state. The storage owner supplies a fresh path and sealed bytes: at least three, and within the single-request limit, because the conditional replacement it checks is one request. This calls the provider without committing credentials or local settings. Cleanup runs even after a lost create reply; a preexisting path is left intact. The caller must await cleanup even if its app waiter is cancelled. During setup the connection sends rate-limited requests again (§20.8), so a refusal fails the check only once the setup call’s minute is spent.