The simplest and most straightforward way to use this crate is to directly construct a [`Reltime`]
value from a number of seconds, then display or render its string representation via [`Display`]:
```rust
use compact_reltime::Reltime;
let my_duration = Reltime::new(3204898).unwrap();
let my_string = my_duration.to_string(); // my_duration implments Display
assert_eq!(my_string, "5w2d");
```