Implementation of the libp2p `Transport` trait for Unix domain sockets.
# Platform support
This transport only works on Unix platforms.
# Usage
The `UdsConfig` transport supports multiaddresses of the form `/unix//tmp/foo`.
The `UdsConfig` structs implements the `Transport` trait of the `core` library. See the
documentation of `core` and of libp2p in general to learn how to use the `Transport` trait.