NFD

The implementation of this face (+channel and channelfactory) should be very simple. UnixStreamFace class should be simply derived from StreamBase<boost::asio::local::stream_protocol::socket> and the few other things will be very similar to TcpFace.

ChannelFactory should be able to create UnixChannel using the supplied const std::string& unixSocketPath. UnixChannel must support listen operation and may support connect, but it is optional.

There's an API problem in UnixStreamChannelFactory. Both create() overloads can take a string as their only argument, because asio::local::stream_protocol::endpoint has an implicit conversion constructor (both from const char* and std::string). As a consequence, calling e.g. UnixStreamChannelFactory::create("/foo/bar") is ambiguous.