feat: embed terasu inside

vendor/github.com/miekg/dns/client.go

@@ -10,6 +10,8 @@ import (
 	"net"
 	"strings"
 	"time"
+
+	"github.com/fumiama/terasu"
 )
 
 const (
@@ -131,11 +133,23 @@ func (c *Client) DialContext(ctx context.Context, address string) (conn *Conn, e
 	if useTLS {
 		network = strings.TrimSuffix(network, "-tls")
 
-		tlsDialer := tls.Dialer{
-			NetDialer: &d,
-			Config:    c.TLSConfig,
+		var rawConn net.Conn
+		rawConn, err = d.DialContext(ctx, network, address)
+		if err == nil {
+			tlsCn := tls.Client(terasu.NewConn(rawConn), c.TLSConfig)
+			if deadline, ok := ctx.Deadline(); ok {
+				rawConn.SetDeadline(deadline)
+			}
+			err = tlsCn.Handshake()
+			if _, ok := ctx.Deadline(); ok {
+				rawConn.SetDeadline(time.Time{})
+			}
+			if err != nil {
+				rawConn.Close()
+			} else {
+				conn.Conn = tlsCn
+			}
 		}
-		conn.Conn, err = tlsDialer.DialContext(ctx, network, address)
 	} else {
 		conn.Conn, err = d.DialContext(ctx, network, address)
 	}