void explore_child(ModelAction *act, enabled_type_t *is_enabled);
/* return false = thread was already in backtrack */
bool set_backtrack(thread_id_t id);
void explore_child(ModelAction *act, enabled_type_t *is_enabled);
/* return false = thread was already in backtrack */
bool set_backtrack(thread_id_t id);
struct future_value get_future_value() const;
bool increment_future_value();
bool future_value_empty() const;
struct future_value get_future_value() const;
bool increment_future_value();
bool future_value_empty() const;