Add native protocol service plugins

plugins/services/zookeeper_test.go

@@ -0,0 +1,16 @@
+//go:build plugin_zookeeper || !plugin_selective
+
+package services
+
+import "testing"
+
+func TestParseZooKeeperResponse(t *testing.T) {
+	banner, ok := parseZooKeeperResponse([]byte("imok"))
+	if !ok || banner != "ZooKeeper ruok=imok" {
+		t.Fatalf("unexpected zookeeper banner: %q ok=%v", banner, ok)
+	}
+
+	if _, ok := parseZooKeeperResponse([]byte("hello")); ok {
+		t.Fatal("unexpected match for non-zookeeper response")
+	}
+}