change box addr for zfs send

box.go

@@ -416,3 +416,8 @@ func (b *Box) SSHExec(cmd string) (buf *bytes.Buffer, err error) {
 	buf, err = b.ssh.exec(cmd)
 	return
 }
+
+func (b *Box) Host() string {
+	s := strings.Split(string(b.Addr), `:`)
+	return s[0]
+}