use a sync.Pool for ACK frames

internal/wire/ack_frame_pool_test.go

@@ -0,0 +1,29 @@
+package wire
+
+import (
+	"math/rand"
+	"time"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("ACK Frame (for IETF QUIC)", func() {
+	It("gets an ACK frame from the pool", func() {
+		for i := 0; i < 100; i++ {
+			ack := GetAckFrame()
+			Expect(ack.AckRanges).To(BeEmpty())
+			Expect(ack.ECNCE).To(BeZero())
+			Expect(ack.ECT0).To(BeZero())
+			Expect(ack.ECT1).To(BeZero())
+			Expect(ack.DelayTime).To(BeZero())
+
+			ack.AckRanges = make([]AckRange, rand.Intn(10))
+			ack.ECNCE = 1
+			ack.ECT0 = 2
+			ack.ECT1 = 3
+			ack.DelayTime = time.Hour
+			PutAckFrame(ack)
+		}
+	})
+})