diff --git a/common/buf/buffer.go b/common/buf/buffer.go
index 2d6705e6b..ec2556ba1 100644
--- a/common/buf/buffer.go
+++ b/common/buf/buffer.go
@@ -13,10 +13,10 @@ type Supplier func([]byte) (int, error)
 // quickly.
 type Buffer struct {
 	v    []byte
-	pool Pool
+	pool *Pool
 
-	start int
-	end   int
+	start int32
+	end   int32
 }
 
 // Release recycles the buffer into an internal buffer pool.
@@ -48,25 +48,25 @@ func (b *Buffer) AppendBytes(bytes ...byte) int {
 // Append appends a byte array to the end of the buffer.
 func (b *Buffer) Append(data []byte) int {
 	nBytes := copy(b.v[b.end:], data)
-	b.end += nBytes
+	b.end += int32(nBytes)
 	return nBytes
 }
 
 // AppendSupplier appends the content of a BytesWriter to the buffer.
 func (b *Buffer) AppendSupplier(writer Supplier) error {
 	nBytes, err := writer(b.v[b.end:])
-	b.end += nBytes
+	b.end += int32(nBytes)
 	return err
 }
 
 // Byte returns the bytes at index.
 func (b *Buffer) Byte(index int) byte {
-	return b.v[b.start+index]
+	return b.v[b.start+int32(index)]
 }
 
 // SetByte sets the byte value at index.
 func (b *Buffer) SetByte(index int, value byte) {
-	b.v[b.start+index] = value
+	b.v[b.start+int32(index)] = value
 }
 
 // Bytes returns the content bytes of this Buffer.
@@ -78,7 +78,7 @@ func (b *Buffer) Bytes() []byte {
 func (b *Buffer) Reset(writer Supplier) error {
 	nBytes, err := writer(b.v)
 	b.start = 0
-	b.end = nBytes
+	b.end = int32(nBytes)
 	return err
 }
 
@@ -90,7 +90,7 @@ func (b *Buffer) BytesRange(from, to int) []byte {
 	if to < 0 {
 		to += b.Len()
 	}
-	return b.v[b.start+from : b.start+to]
+	return b.v[b.start+int32(from) : b.start+int32(to)]
 }
 
 // BytesFrom returns a slice of this Buffer starting from the given position.
@@ -98,7 +98,7 @@ func (b *Buffer) BytesFrom(from int) []byte {
 	if from < 0 {
 		from += b.Len()
 	}
-	return b.v[b.start+from : b.end]
+	return b.v[b.start+int32(from) : b.end]
 }
 
 // BytesTo returns a slice of this Buffer from start to the given position.
@@ -106,7 +106,7 @@ func (b *Buffer) BytesTo(to int) []byte {
 	if to < 0 {
 		to += b.Len()
 	}
-	return b.v[b.start : b.start+to]
+	return b.v[b.start : b.start+int32(to)]
 }
 
 // Slice cuts the buffer at the given position.
@@ -120,8 +120,8 @@ func (b *Buffer) Slice(from, to int) {
 	if to < from {
 		panic("Invalid slice")
 	}
-	b.end = b.start + to
-	b.start += from
+	b.end = b.start + int32(to)
+	b.start += int32(from)
 }
 
 // SliceFrom cuts the buffer at the given position.
@@ -129,7 +129,7 @@ func (b *Buffer) SliceFrom(from int) {
 	if from < 0 {
 		from += b.Len()
 	}
-	b.start += from
+	b.start += int32(from)
 }
 
 // Len returns the length of the buffer content.
@@ -137,7 +137,7 @@ func (b *Buffer) Len() int {
 	if b == nil {
 		return 0
 	}
-	return b.end - b.start
+	return int(b.end - b.start)
 }
 
 // IsEmpty returns true if the buffer is empty.
@@ -147,13 +147,13 @@ func (b *Buffer) IsEmpty() bool {
 
 // IsFull returns true if the buffer has no more room to grow.
 func (b *Buffer) IsFull() bool {
-	return b.end == len(b.v)
+	return b.end == int32(len(b.v))
 }
 
 // Write implements Write method in io.Writer.
 func (b *Buffer) Write(data []byte) (int, error) {
 	nBytes := copy(b.v[b.end:], data)
-	b.end += nBytes
+	b.end += int32(nBytes)
 	return nBytes, nil
 }
 
@@ -166,7 +166,7 @@ func (b *Buffer) Read(data []byte) (int, error) {
 	if nBytes == b.Len() {
 		b.Clear()
 	} else {
-		b.start += nBytes
+		b.start += int32(nBytes)
 	}
 	return nBytes, nil
 }
diff --git a/common/buf/buffer_pool.go b/common/buf/buffer_pool.go
index d66047305..7904ee9a7 100644
--- a/common/buf/buffer_pool.go
+++ b/common/buf/buffer_pool.go
@@ -5,21 +5,13 @@ import (
 )
 
 // Pool provides functionality to generate and recycle buffers on demand.
-type Pool interface {
-	// Allocate either returns a unused buffer from the pool, or generates a new one from system.
-	Allocate() *Buffer
-	// Free recycles the given buffer.
-	Free(*Buffer)
-}
-
-// SyncPool is a buffer pool based on sync.Pool
-type SyncPool struct {
+type Pool struct {
 	allocator *sync.Pool
 }
 
-// NewSyncPool creates a SyncPool with given buffer size.
-func NewSyncPool(bufferSize uint32) *SyncPool {
-	pool := &SyncPool{
+// NewPool creates a SyncPool with given buffer size.
+func NewPool(bufferSize uint32) *Pool {
+	pool := &Pool{
 		allocator: &sync.Pool{
 			New: func() interface{} { return make([]byte, bufferSize) },
 		},
@@ -27,16 +19,16 @@ func NewSyncPool(bufferSize uint32) *SyncPool {
 	return pool
 }
 
-// Allocate implements Pool.Allocate().
-func (p *SyncPool) Allocate() *Buffer {
+// Allocate either returns a unused buffer from the pool, or generates a new one from system.
+func (p *Pool) Allocate() *Buffer {
 	return &Buffer{
 		v:    p.allocator.Get().([]byte),
 		pool: p,
 	}
 }
 
-// Free implements Pool.Free().
-func (p *SyncPool) Free(buffer *Buffer) {
+// // Free recycles the given buffer.
+func (p *Pool) Free(buffer *Buffer) {
 	if buffer.v != nil {
 		p.allocator.Put(buffer.v)
 	}
@@ -47,6 +39,4 @@ const (
 	Size = 2 * 1024
 )
 
-var (
-	mediumPool Pool = NewSyncPool(Size)
-)
+var mediumPool = NewPool(Size)
diff --git a/common/buf/buffer_test.go b/common/buf/buffer_test.go
index af05057ec..f7146b49f 100644
--- a/common/buf/buffer_test.go
+++ b/common/buf/buffer_test.go
@@ -58,7 +58,7 @@ func TestBufferWrite(t *testing.T) {
 func TestSyncPool(t *testing.T) {
 	assert := With(t)
 
-	p := NewSyncPool(32)
+	p := NewPool(32)
 	b := p.Allocate()
 	assert(b.Len(), Equals, 0)