This command makes the current process a server for parallel training. It will then accept connections from clients and will be able to invoke commands on the clients and control parallel training.
If port is specified, it sets the port to be used when listening for new clients. Values between 2001 and 6999 are often free. Otherwise, a random free port will be selected. This command always returns the port number used. It is important to save this value so clients can use it when connecting.
To start the server with a random port and save the port in the variable "serverPort":
lens> set serverPort [startServer]