inline static uint32 push_back_return_index(Tx& x, const Ty& y)
{
uint32 old_size = x.size();
x.push_back(y);
return old_size;
}
inline static uint32 push_back_return_index(Tx& x, const Ty& y)
{
uint32 old_size = x.size();
x.push_back(y);
return old_size;
}