class TransportManager {

    @Nullable
    public TransportClient getTransportClient(String transportName, String caller) {
        try {
            return getTransportClientOrThrow(transportName, caller);
        } catch (TransportNotRegisteredException e) {
            Slog.w(TAG, "Transport " + transportName + " not registered");
            return null;
        }
    }

      TransportManager(@UserIdInt int userId, Context context, Set<ComponentName> whitelist,
            String selectedTransport);
    @VisibleForTesting  TransportManager(
            @UserIdInt int userId,
            Context context,
            Set<ComponentName> whitelist,
            String selectedTransport,
            TransportClientManager transportClientManager);

}