feat(dns): add parallel query (#5239)

app/dns/nameserver.go

@@ -20,6 +20,9 @@ import (
 type Server interface {
 	// Name of the Client.
 	Name() string
+
+	IsDisableCache() bool
+
 	// QueryIP sends IP queries to its configured server.
 	QueryIP(ctx context.Context, domain string, option dns.IPOption) ([]net.IP, uint32, error)
 }
@@ -38,6 +41,7 @@ type Client struct {
 	finalQuery    bool
 	ipOption      *dns.IPOption
 	checkSystem   bool
+	policyID      uint32
 }
 
 // NewServer creates a name server object according to the network destination url.
@@ -199,6 +203,7 @@ func NewClient(
 		client.finalQuery = ns.FinalQuery
 		client.ipOption = &ipOption
 		client.checkSystem = checkSystem
+		client.policyID = ns.PolicyID
 		return nil
 	})
 	return client, err
@@ -209,10 +214,6 @@ func (c *Client) Name() string {
 	return c.server.Name()
 }
 
-func (c *Client) IsFinalQuery() bool {
-	return c.finalQuery
-}
-
 // QueryIP sends DNS query to the name server with the client's IP.
 func (c *Client) QueryIP(ctx context.Context, domain string, option dns.IPOption) ([]net.IP, uint32, error) {
 	if c.checkSystem {