// for some reason i do need that lock_guard here.. even though output is itself lock guarded. maybe some lazyness in the evauation of the to_string(out_id++)? who kon
// anyway this fixes the problem, i'll understand it some other time.
std::cout<<"raw space of UF hash data: "<<(2*getNumKeys*sizeof(T))/1024/1024<<" MB"<<std::endl;// 2x because each key of type T is associated to a value of type T