This crate provides a [Cell] type (like the standard library’s
Cell) with methods for safely mutating and inspecting the
inner value by reference ([with] and [with_mut]).
For [Copy] types, this is implemented with get and
set, but through an extension trait, this crate
provides those same operations for types that are [Default] but not
[Copy]. A [get] method is also available for types that are both
[Default] and [Clone].
This crate depends only on [core], so it can be used inside no_std
environments.
```rust use cell_ref::{Cell, CellExt};
let c1 = Cell::new(2u8); c1.withmut(|x| *x += 3); assert!(c1.get() == 5);
let c2 = Cell::new(vec![1, 2, 3]);
c2.withmut(|v| v.push(4)); // Works even though Vec isn't Copy
asserteq!(c2.with(Vec::len), 4);
let v = c2.get(); // Clones the vector
```