Opens a socket or named pipe at {address} and listens for |RPC| messages. Clients can send |API| commands to the address to control Nvim. Returns the address string. If {address} does not contain a colon ":" it is interpreted as a named pipe or Unix domain socket path. Example: if has('win32') call serverstart('\.\pipe\nvim-pipe-1234') else call serverstart('nvim.sock') endif If {address} contains a colon ":" it is interpreted as a TCP address where the last ":" separates the host and port. Assigns a random port if it is empty or 0. Supports IPv4/IPv6. Example: :call serverstart('::1:12345') If no address is given, it is equivalent to: :call serverstart(tempname()) |$NVIM_LISTEN_ADDRESS| is set to {address} if not already set.