docs(readme): add example usage

Author: BobAnkh

README.md

@@ -5,7 +5,25 @@
 [![docs.rs](https://img.shields.io/badge/docs.rs-bandwidth-blue?logo=data:image/svg+xml;base64,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)](https://docs.rs/bandwidth)
 [![LICENSE Apache-2.0](https://img.shields.io/github/license/stack-rs/bandwidth?logo=Apache)](https://github.com/stack-rs/bandwidth/blob/main/LICENSE)
 
-A library for representing bandwidth speed in a variety of units, mimicking the `core::time::Duration` struct.
+A library for representing bandwidth speed in a variety of units, mimicking the `core::time::Duration` struct.]
+
+## Usage
+
+More detailed usage can be found on [documentation](https://docs.rs/bandwidth).
+
+```rust
+use bandwidth::Bandwidth;
+
+let five_gbps = Bandwidth::from_gbps(5);
+assert_eq!(five_gbps, Bandwidth::from_mbps(5_000));
+assert_eq!(five_gbps, Bandwidth::from_kbps(5_000_000));
+assert_eq!(five_gbps, Bandwidth::from_bps(5_000_000_000));
+
+let ten_gbps = Bandwidth::from_gbps(10);
+let seven_bps = Bandwidth::from_bps(7);
+let total = ten_gbps + seven_bps;
+assert_eq!(total, Bandwidth::new(10, 7));
+```
 
 ## Maintainer