Add pools for packetack

wrappers/packetack/client_abridged.go

 		return nil
 	case packetLength < clientAbridgedLargePacketLength:
 		length24 := utils.ToUint24(uint32(packetLength))
-		buf := bytes.Buffer{}
+
+		buf := acquireClientBytesBuffer()
+		defer releaseClientBytesBuffer(buf)
 
 		buf.WriteByte(byte(clientAbridgedSmallPacketLength))
 		buf.Write(length24[:])

wrappers/packetack/client_intermediate_secure.go

 package packetack
 
 import (
-	"bytes"
 	"encoding/binary"
 	"fmt"
 	"math/rand"
 		return nil
 	}
 
-	buf := bytes.Buffer{}
+	buf := acquireClientBytesBuffer()
+	defer releaseClientBytesBuffer(buf)
+
 	paddingLength := rand.Intn(4)
 	buf.Grow(4 + len(packet) + paddingLength)
 
-	binary.Write(&buf, binary.LittleEndian, uint32(len(packet)+paddingLength)) // nolint: errcheck
+	binary.Write(buf, binary.LittleEndian, uint32(len(packet)+paddingLength)) // nolint: errcheck
 	buf.Write(packet)
 	buf.Write(make([]byte, paddingLength))
 

wrappers/packetack/pools.go

+package packetack
+
+import (
+	"bytes"
+	"sync"
+)
+
+var (
+	poolClientBytesBuffer = sync.Pool{
+		New: func() interface{} {
+			return &bytes.Buffer{}
+		},
+	}
+	poolProxyBytesBuffer = sync.Pool{
+		New: func() interface{} {
+			return &bytes.Buffer{}
+		},
+	}
+)
+
+func acquireClientBytesBuffer() *bytes.Buffer {
+	return poolClientBytesBuffer.Get().(*bytes.Buffer)
+}
+
+func acquireProxyBytesBuffer() *bytes.Buffer {
+	return poolProxyBytesBuffer.Get().(*bytes.Buffer)
+}
+
+func releaseClientBytesBuffer(buf *bytes.Buffer) {
+	buf.Reset()
+	poolClientBytesBuffer.Put(buf)
+}
+
+func releaseProxyBytesBuffer(buf *bytes.Buffer) {
+	buf.Reset()
+	poolProxyBytesBuffer.Put(buf)
+}

wrappers/packetack/proxy.go

 }
 
 func (w *wrapperProxy) Write(packet conntypes.Packet, acks *conntypes.ConnectionAcks) error {
-	buf := bytes.Buffer{}
+	buf := acquireProxyBytesBuffer()
+	defer releaseProxyBytesBuffer(buf)
 
 	flags := w.flags
 	if acks.Quick {