* @param num_peers Number of peers to start.
* @param tmain Main function to run once the testbed is ready.
* @param tmain_cls Closure for 'tmain'.
* @param num_peers Number of peers to start.
* @param tmain Main function to run once the testbed is ready.
* @param tmain_cls Closure for 'tmain'.
* @param cleaner Cleaner for destroyed incoming tunnels.
* @param handlers Message handlers.
* @param ports Ports the peers offer.
* @param cleaner Cleaner for destroyed incoming tunnels.
* @param handlers Message handlers.
* @param ports Ports the peers offer.