static inline void set_feature(enum features_id feature_id)
{
   int slot = feature_id / 64;
   uint64_t mask = 1ull << (feature_id & 63);
   vrend_state.features[slot] |= mask;
}
static inline void set_feature(enum features_id feature_id)
{
   int slot = feature_id / 64;
   uint64_t mask = 1ull << (feature_id & 63);
   vrend_state.features[slot] |= mask;
}