Is your feature request related to a problem? Please describe.
I was not aware that is is possible to bind to a specific interface address (typically localhost for security reasons) and have been using allow_ip() as an inferior substitute.

Describe why the feature or enhancement you are proposing fits the library.
The feature is supported already but not documented.

Describe the solution you'd like
Document bind_address() in README.md similar to port() and bind_socket()

Describe alternatives you've considered
It would be nice if bind_address() alternately accepted an address in the same IP string format used by allow_ip() rather than forcing the caller to construct a struct sockaddr.

Additional context