remove 6 byte packet numbers

internal/protocol/packet_number.go

@@ -58,8 +58,5 @@ func GetPacketNumberLength(packetNumber PacketNumber) PacketNumberLen {
 	if packetNumber < (1 << (uint8(PacketNumberLen2) * 8)) {
 		return PacketNumberLen2
 	}
-	if packetNumber < (1 << (uint8(PacketNumberLen4) * 8)) {
-		return PacketNumberLen4
-	}
-	return PacketNumberLen6
+	return PacketNumberLen4
 }

internal/protocol/packet_number_test.go

@@ -228,9 +228,5 @@ var _ = Describe("packet number calculation", func() {
 		It("4 byte", func() {
 			Expect(GetPacketNumberLength(0xFFFFFFFF)).To(Equal(PacketNumberLen4))
 		})
-
-		It("6 byte", func() {
-			Expect(GetPacketNumberLength(0xFFFFFFFFFFFF)).To(Equal(PacketNumberLen6))
-		})
 	})
 })

internal/protocol/protocol.go

@@ -19,8 +19,6 @@ const (
 	PacketNumberLen2 PacketNumberLen = 2
 	// PacketNumberLen4 is a packet number length of 4 bytes
 	PacketNumberLen4 PacketNumberLen = 4
-	// PacketNumberLen6 is a packet number length of 6 bytes
-	PacketNumberLen6 PacketNumberLen = 6
 )
 
 // The PacketType is the Long Header Type