https://github.com/frehberg/tokio-tower-demo-transport
The rust API-doc of the crate tokio-tower contains an example, that is illustrating the usage of Sink and Stream for the transport. AFAICS, this example should be presented more prominently.
https://docs.rs/tokio-tower/latest/tokio_tower/
For the Crate https://github.com/tower-rs/tokio-tower