vec_validate (um->connection_peekers, num_threads - 1);
vec_validate (um->peekers_readers_locks, num_threads - 1);
vec_validate (um->peekers_write_locks, num_threads - 1);
vec_validate (um->connection_peekers, num_threads - 1);
vec_validate (um->peekers_readers_locks, num_threads - 1);
vec_validate (um->peekers_write_locks, num_threads - 1);