Doc unclear about types of clients/servers tokio-proto can make

[nicholasbishop]

In the "What is Tokio?" doc it says:

The tokio-proto layer is the easiest way to build servers and clients. All you have to do is handle message serialization; proto takes care of the rest.

It's unclear how to interpret this because it doesn't say anything about the transport layer. The examples are mostly for TCP servers, but I gather that tokio-proto can be used with other types of networking? If so it seems incorrect to say that you only have to handle message serialization.