use go 1.12

Signed-off-by: hongming <talonwan@yunify.com>

vendor/github.com/lucas-clemente/quic-go/internal/ackhandler/packet.go

@@ -0,0 +1,29 @@
+package ackhandler
+
+import (
+	"time"
+
+	"github.com/lucas-clemente/quic-go/internal/protocol"
+	"github.com/lucas-clemente/quic-go/internal/wire"
+)
+
+// A Packet is a packet
+type Packet struct {
+	PacketNumber    protocol.PacketNumber
+	PacketType      protocol.PacketType
+	Frames          []wire.Frame
+	Length          protocol.ByteCount
+	EncryptionLevel protocol.EncryptionLevel
+	SendTime        time.Time
+
+	largestAcked protocol.PacketNumber // if the packet contains an ACK, the LargestAcked value of that ACK
+
+	// There are two reasons why a packet cannot be retransmitted:
+	// * it was already retransmitted
+	// * this packet is a retransmission, and we already received an ACK for the original packet
+	canBeRetransmitted      bool
+	includedInBytesInFlight bool
+	retransmittedAs         []protocol.PacketNumber
+	isRetransmission        bool // we need a separate bool here because 0 is a valid packet number
+	retransmissionOf        protocol.PacketNumber
+}