update vendors

vendor/github.com/fatedier/kcp-go/tx.go

@@ -0,0 +1,25 @@
+package kcp
+
+import (
+	"sync/atomic"
+
+	"github.com/pkg/errors"
+	"golang.org/x/net/ipv4"
+)
+
+func (s *UDPSession) defaultTx(txqueue []ipv4.Message) {
+	nbytes := 0
+	npkts := 0
+	for k := range txqueue {
+		if n, err := s.conn.WriteTo(txqueue[k].Buffers[0], txqueue[k].Addr); err == nil {
+			nbytes += n
+			npkts++
+			xmitBuf.Put(txqueue[k].Buffers[0])
+		} else {
+			s.notifyWriteError(errors.WithStack(err))
+			break
+		}
+	}
+	atomic.AddUint64(&DefaultSnmp.OutPkts, uint64(npkts))
+	atomic.AddUint64(&DefaultSnmp.OutBytes, uint64(nbytes))
+}