add persistent flag --kind

use it to configure the client

internal/xair/option.go

@@ -1,18 +1,10 @@
 package xair
 
-import "strings"
-
 type Option func(*engine)
 
 func WithKind(kind string) Option {
-	if strings.EqualFold(kind, "x32") {
-		return func(c *engine) {
-			c.Kind = kind
-			c.addressMap = x32AddressMap
-		}
-	}
-	return func(c *engine) {
-		c.Kind = "xair"
-		c.addressMap = xairAddressMap
+	return func(e *engine) {
+		e.Kind = MixerKind(kind)
+		e.addressMap = addressMapForMixerKind(e.Kind)
 	}
 }