| Declare lazily evaluated constant |  |   |
| Std::cell |  | |
std::cell:LazyCell | | |
std::sync::LazyLock | | |
Store different types in one vector with Box<dyn Trait> | | |
Share mutable structure between owners with Rc<RefCell<T>> | | |
Return borrowed or owned text with Cow<str> | | |
Update text using mem::swap, mem::take and mem::replace | | |