Why use struct instead of pointer？

[super9du]

amqp/connection.go

Line 223 in e6b33f4

func Open(conn io.ReadWriteCloser, config Config) (*Connection, error) {

func Open(conn io.ReadWriteCloser, config Config) (*Connection, error) {
	c := &Connection{
		conn:      conn,
		writer:    &writer{bufio.NewWriter(conn)},
		channels:  make(map[uint16]*Channel),
		rpc:       make(chan message),
		sends:     make(chan time.Time),
		errors:    make(chan *Error, 1),
		deadlines: make(chan readDeadliner, 1),
	}
	go c.reader(conn)
	return c, c.open(config)
}

[super9du]

the arg "config" is not a pointer.