net.dial() network参数的全部可选值及其含义

源码有啊，这是官方的： ```Go // Dial connects to the address on the named network. // // Known networks are "tcp", "tcp4" (IPv4-only), "tcp6" (IPv6-only), // "udp", "udp4" (IPv4-only), "udp6" (IPv6-only), "ip", "ip4" // (IPv4-only), "ip6" (IPv6-only), "unix", "unixgram" and // "unixpacket". // // For TCP and UDP networks, addresses have the form host:port. // If host is a literal IPv6 address it must be enclosed // in square brackets as in "[::1]:80" or "[ipv6-host%zone]:80". // The functions JoinHostPort and SplitHostPort manipulate addresses // in this form. // If the host is empty, as in ":80", the local system is assumed. // // Examples: // Dial("tcp", "192.0.2.1:80") // Dial("tcp", "golang.org:http") // Dial("tcp", "[2001:db8::1]:http") // Dial("tcp", "[fe80::1%lo0]:80") // Dial("tcp", ":80") // // For IP networks, the network must be "ip", "ip4" or "ip6" followed // by a colon and a protocol number or name and the addr must be a // literal IP address. // // Examples: // Dial("ip4:1", "192.0.2.1") // Dial("ip6:ipv6-icmp", "2001:db8::1") // // For Unix networks, the address must be a file system path. func Dial(network, address string) (Conn, error) { var d Dialer return d.Dial(network, address) } ```