Sockets.PipeServer allows connections with AF_UNIX/AF_LOCAL connections (named sockets) not named pipes AKA FIFOs. These are completely different gizmos, at least on Linux. Other than being named and providing communication, there are probably more differences than similarities between named sockets and named pipes. Pipes are unidirectional, sockets are bidirectional. A FIFO must already exist when the reader opens it, the socket must not exist when the server binds to it.
Julia is a good way to learn about and experiment with IPC, but this misleading name is not a help.