diff --git a/common/buf/buffer_pool.go b/common/buf/buffer_pool.go
index dcb1ff436..15c94b665 100644
--- a/common/buf/buffer_pool.go
+++ b/common/buf/buffer_pool.go
@@ -118,7 +118,7 @@ func getDefaultPoolSize() uint32 {
 }
 
 func init() {
-	var size uint32 = getDefaultPoolSize()
+	size := getDefaultPoolSize()
 	sizeStr := os.Getenv(poolSizeEnvKey)
 	if len(sizeStr) > 0 {
 		customSize, err := strconv.ParseUint(sizeStr, 10, 32)
diff --git a/common/buf/buffered_reader.go b/common/buf/buffered_reader.go
index c3e956e58..4a9479214 100644
--- a/common/buf/buffered_reader.go
+++ b/common/buf/buffered_reader.go
@@ -11,7 +11,7 @@ type BufferedReader struct {
 	buffered bool
 }
 
-// NewReader creates a new BufferedReader based on an io.Reader.
+// NewBufferedReader creates a new BufferedReader based on an io.Reader.
 func NewBufferedReader(rawReader io.Reader) *BufferedReader {
 	return &BufferedReader{
 		reader:   rawReader,
diff --git a/common/buf/buffered_writer.go b/common/buf/buffered_writer.go
index 9ae34230a..c1d0e6c51 100644
--- a/common/buf/buffered_writer.go
+++ b/common/buf/buffered_writer.go
@@ -14,7 +14,7 @@ type BufferedWriter struct {
 	buffered bool
 }
 
-// NewWriter creates a new BufferedWriter.
+// NewBufferedWriter creates a new BufferedWriter.
 func NewBufferedWriter(rawWriter io.Writer) *BufferedWriter {
 	return &BufferedWriter{
 		writer:   rawWriter,
diff --git a/common/buf/buffered_writer_test.go b/common/buf/buffered_writer_test.go
index 1aca3c9a3..d22db443b 100644
--- a/common/buf/buffered_writer_test.go
+++ b/common/buf/buffered_writer_test.go
@@ -24,7 +24,7 @@ func TestBufferedWriter(t *testing.T) {
 
 	assert.Bool(content.IsEmpty()).IsTrue()
 
-	writer.SetBuffered(false)
+	assert.Error(writer.SetBuffered(false)).IsNil()
 	assert.Int(content.Len()).Equals(16)
 }
 
diff --git a/common/buf/io.go b/common/buf/io.go
index 94406eb79..0e24241f5 100644
--- a/common/buf/io.go
+++ b/common/buf/io.go
@@ -76,7 +76,7 @@ func NewReader(reader io.Reader) Reader {
 
 // ToBytesReader converts a Reaaer to io.Reader.
 func ToBytesReader(stream Reader) io.Reader {
-	return &BufferToBytesReader{
+	return &bufferToBytesReader{
 		stream: stream,
 	}
 }
@@ -90,7 +90,7 @@ func NewWriter(writer io.Writer) Writer {
 
 // ToBytesWriter converts a Writer to io.Writer
 func ToBytesWriter(writer Writer) io.Writer {
-	return &BytesToBufferWriter{
+	return &bytesToBufferWriter{
 		writer: writer,
 	}
 }
diff --git a/common/buf/reader.go b/common/buf/reader.go
index 270668a94..391de9b94 100644
--- a/common/buf/reader.go
+++ b/common/buf/reader.go
@@ -43,15 +43,14 @@ func (v *BytesToBufferReader) Read() (*Buffer, error) {
 	return buffer, nil
 }
 
-type BufferToBytesReader struct {
+type bufferToBytesReader struct {
 	stream  Reader
 	current *Buffer
 	err     error
 }
 
-// Fill fills in the internal buffer.
-// Private: Visible for testing.
-func (v *BufferToBytesReader) Fill() {
+// fill fills in the internal buffer.
+func (v *bufferToBytesReader) fill() {
 	b, err := v.stream.Read()
 	v.current = b
 	if err != nil {
@@ -60,13 +59,13 @@ func (v *BufferToBytesReader) Fill() {
 	}
 }
 
-func (v *BufferToBytesReader) Read(b []byte) (int, error) {
+func (v *bufferToBytesReader) Read(b []byte) (int, error) {
 	if v.err != nil {
 		return 0, v.err
 	}
 
 	if v.current == nil {
-		v.Fill()
+		v.fill()
 		if v.err != nil {
 			return 0, v.err
 		}
diff --git a/common/buf/writer.go b/common/buf/writer.go
index e79fe46e8..7a2601a99 100644
--- a/common/buf/writer.go
+++ b/common/buf/writer.go
@@ -23,11 +23,11 @@ func (v *BufferToBytesWriter) Write(buffer *Buffer) error {
 	return nil
 }
 
-type BytesToBufferWriter struct {
+type bytesToBufferWriter struct {
 	writer Writer
 }
 
-func (v *BytesToBufferWriter) Write(payload []byte) (int, error) {
+func (v *bytesToBufferWriter) Write(payload []byte) (int, error) {
 	bytesWritten := 0
 	size := len(payload)
 	for size > 0 {