diff --git a/gee-rpc/day1-codec/codec/codec.go b/gee-rpc/day1-codec/codec/codec.go
index 54d2e56..ba28fba 100644
--- a/gee-rpc/day1-codec/codec/codec.go
+++ b/gee-rpc/day1-codec/codec/codec.go
@@ -2,7 +2,6 @@ package codec
 
 import (
 	"io"
-	"sync"
 )
 
 type Header struct {
@@ -11,10 +10,6 @@ type Header struct {
 	Error         string
 }
 
-var HeaderPool = sync.Pool{
-	New: func() interface{} { return &Header{} },
-}
-
 type Codec interface {
 	io.Closer
 	ReadHeader(*Header) error
diff --git a/gee-rpc/day1-codec/server.go b/gee-rpc/day1-codec/server.go
index 5a8a9bf..06ef763 100644
--- a/gee-rpc/day1-codec/server.go
+++ b/gee-rpc/day1-codec/server.go
@@ -89,15 +89,14 @@ type request struct {
 }
 
 func (server *Server) readRequestHeader(cc codec.Codec) (*codec.Header, error) {
-	h, _ := codec.HeaderPool.Get().(*codec.Header)
-	if err := cc.ReadHeader(h); err != nil {
-		codec.HeaderPool.Put(h)
+	var h codec.Header
+	if err := cc.ReadHeader(&h); err != nil {
 		if err != io.EOF && err != io.ErrUnexpectedEOF {
 			log.Println("rpc server: read header error:", err)
 		}
 		return nil, err
 	}
-	return h, nil
+	return &h, nil
 }
 
 func (server *Server) readRequest(cc codec.Codec) (*request, error) {
@@ -121,7 +120,6 @@ func (server *Server) sendResponse(cc codec.Codec, h *codec.Header, body interfa
 	if err := cc.Write(h, body); err != nil {
 		log.Println("rpc server: write response error:", err)
 	}
-	codec.HeaderPool.Put(h) // recycle Header object
 }
 
 func (server *Server) handleRequest(cc codec.Codec, req *request, sending *sync.Mutex, wg *sync.WaitGroup) {
diff --git a/gee-rpc/day2-client/client.go b/gee-rpc/day2-client/client.go
index 2cbbb0c..3fd885e 100644
--- a/gee-rpc/day2-client/client.go
+++ b/gee-rpc/day2-client/client.go
@@ -34,7 +34,8 @@ func (call *Call) done() {
 // multiple goroutines simultaneously.
 type Client struct {
 	cc      codec.Codec
-	sending sync.Mutex // protect sending a complete request
+	sending sync.Mutex // protect following
+	header  codec.Header
 	mu      sync.Mutex // protect following
 	seq     uint64
 	pending map[uint64]*Call
@@ -101,14 +102,12 @@ func (client *Client) send(call *Call) {
 	}
 
 	// prepare request header
-	h, _ := codec.HeaderPool.Get().(*codec.Header)
-	h.ServiceMethod = call.ServiceMethod
-	h.Seq = seq
-	h.Error = ""
-	defer codec.HeaderPool.Put(h)
+	client.header.ServiceMethod = call.ServiceMethod
+	client.header.Seq = seq
+	client.header.Error = ""
 
 	// encode and send the request
-	if err := client.cc.Write(h, call.Args); err != nil {
+	if err := client.cc.Write(&client.header, call.Args); err != nil {
 		call := client.removeCall(seq)
 		// call may be nil, it usually means that Write partially failed,
 		// client has received the response and handled
@@ -120,9 +119,9 @@ func (client *Client) send(call *Call) {
 }
 
 func (client *Client) receive() {
-	var h codec.Header
 	var err error
 	for err == nil {
+		var h codec.Header
 		if err = client.cc.ReadHeader(&h); err != nil {
 			break
 		}
diff --git a/gee-rpc/day2-client/codec/codec.go b/gee-rpc/day2-client/codec/codec.go
index 54d2e56..ba28fba 100644
--- a/gee-rpc/day2-client/codec/codec.go
+++ b/gee-rpc/day2-client/codec/codec.go
@@ -2,7 +2,6 @@ package codec
 
 import (
 	"io"
-	"sync"
 )
 
 type Header struct {
@@ -11,10 +10,6 @@ type Header struct {
 	Error         string
 }
 
-var HeaderPool = sync.Pool{
-	New: func() interface{} { return &Header{} },
-}
-
 type Codec interface {
 	io.Closer
 	ReadHeader(*Header) error
diff --git a/gee-rpc/day2-client/server.go b/gee-rpc/day2-client/server.go
index 5a8a9bf..06ef763 100644
--- a/gee-rpc/day2-client/server.go
+++ b/gee-rpc/day2-client/server.go
@@ -89,15 +89,14 @@ type request struct {
 }
 
 func (server *Server) readRequestHeader(cc codec.Codec) (*codec.Header, error) {
-	h, _ := codec.HeaderPool.Get().(*codec.Header)
-	if err := cc.ReadHeader(h); err != nil {
-		codec.HeaderPool.Put(h)
+	var h codec.Header
+	if err := cc.ReadHeader(&h); err != nil {
 		if err != io.EOF && err != io.ErrUnexpectedEOF {
 			log.Println("rpc server: read header error:", err)
 		}
 		return nil, err
 	}
-	return h, nil
+	return &h, nil
 }
 
 func (server *Server) readRequest(cc codec.Codec) (*request, error) {
@@ -121,7 +120,6 @@ func (server *Server) sendResponse(cc codec.Codec, h *codec.Header, body interfa
 	if err := cc.Write(h, body); err != nil {
 		log.Println("rpc server: write response error:", err)
 	}
-	codec.HeaderPool.Put(h) // recycle Header object
 }
 
 func (server *Server) handleRequest(cc codec.Codec, req *request, sending *sync.Mutex, wg *sync.WaitGroup) {
diff --git a/gee-rpc/day3-service/client.go b/gee-rpc/day3-service/client.go
index 2cbbb0c..3fd885e 100644
--- a/gee-rpc/day3-service/client.go
+++ b/gee-rpc/day3-service/client.go
@@ -34,7 +34,8 @@ func (call *Call) done() {
 // multiple goroutines simultaneously.
 type Client struct {
 	cc      codec.Codec
-	sending sync.Mutex // protect sending a complete request
+	sending sync.Mutex // protect following
+	header  codec.Header
 	mu      sync.Mutex // protect following
 	seq     uint64
 	pending map[uint64]*Call
@@ -101,14 +102,12 @@ func (client *Client) send(call *Call) {
 	}
 
 	// prepare request header
-	h, _ := codec.HeaderPool.Get().(*codec.Header)
-	h.ServiceMethod = call.ServiceMethod
-	h.Seq = seq
-	h.Error = ""
-	defer codec.HeaderPool.Put(h)
+	client.header.ServiceMethod = call.ServiceMethod
+	client.header.Seq = seq
+	client.header.Error = ""
 
 	// encode and send the request
-	if err := client.cc.Write(h, call.Args); err != nil {
+	if err := client.cc.Write(&client.header, call.Args); err != nil {
 		call := client.removeCall(seq)
 		// call may be nil, it usually means that Write partially failed,
 		// client has received the response and handled
@@ -120,9 +119,9 @@ func (client *Client) send(call *Call) {
 }
 
 func (client *Client) receive() {
-	var h codec.Header
 	var err error
 	for err == nil {
+		var h codec.Header
 		if err = client.cc.ReadHeader(&h); err != nil {
 			break
 		}
diff --git a/gee-rpc/day3-service/codec/codec.go b/gee-rpc/day3-service/codec/codec.go
index 54d2e56..ba28fba 100644
--- a/gee-rpc/day3-service/codec/codec.go
+++ b/gee-rpc/day3-service/codec/codec.go
@@ -2,7 +2,6 @@ package codec
 
 import (
 	"io"
-	"sync"
 )
 
 type Header struct {
@@ -11,10 +10,6 @@ type Header struct {
 	Error         string
 }
 
-var HeaderPool = sync.Pool{
-	New: func() interface{} { return &Header{} },
-}
-
 type Codec interface {
 	io.Closer
 	ReadHeader(*Header) error
diff --git a/gee-rpc/day3-service/server.go b/gee-rpc/day3-service/server.go
index f29f33d..6558dad 100644
--- a/gee-rpc/day3-service/server.go
+++ b/gee-rpc/day3-service/server.go
@@ -94,15 +94,14 @@ type request struct {
 }
 
 func (server *Server) readRequestHeader(cc codec.Codec) (*codec.Header, error) {
-	h, _ := codec.HeaderPool.Get().(*codec.Header)
-	if err := cc.ReadHeader(h); err != nil {
-		codec.HeaderPool.Put(h)
+	var h codec.Header
+	if err := cc.ReadHeader(&h); err != nil {
 		if err != io.EOF && err != io.ErrUnexpectedEOF {
 			log.Println("rpc server: read header error:", err)
 		}
 		return nil, err
 	}
-	return h, nil
+	return &h, nil
 }
 
 func (server *Server) findService(serviceMethod string) (svc *service, mtype *methodType, err error) {
@@ -156,7 +155,6 @@ func (server *Server) sendResponse(cc codec.Codec, h *codec.Header, body interfa
 	if err := cc.Write(h, body); err != nil {
 		log.Println("rpc server: write response error:", err)
 	}
-	codec.HeaderPool.Put(h) // recycle Header object
 }
 
 func (server *Server) handleRequest(cc codec.Codec, req *request, sending *sync.Mutex, wg *sync.WaitGroup) {