add packetParse.Empty()

packet_packer.go

@@ -156,3 +156,8 @@ func (p *packetPacker) composeNextPacket(stopWaitingFrame *frames.StopWaitingFra
 
 	return payloadFrames, nil
 }
+
+// Empty returns true if no frames are queued
+func (p *packetPacker) Empty() bool {
+	return p.streamFrameQueue.Front() == nil
+}

packet_packer_test.go

@@ -223,4 +223,14 @@ var _ = Describe("Packet packer", func() {
 			Expect(len(payloadFrames)).To(Equal(1))
 		})
 	})
+
+	It("says whether it is empty", func() {
+		Expect(packer.Empty()).To(BeTrue())
+		f := frames.StreamFrame{
+			StreamID: 5,
+			Data:     []byte{0xDE, 0xCA, 0xFB, 0xAD},
+		}
+		packer.AddStreamFrame(f)
+		Expect(packer.Empty()).To(BeFalse())
+	})
 })