move all the buffer references to util/buf

util/buf/buf.go

@@ -0,0 +1,21 @@
+package buf
+
+import (
+	"bytes"
+)
+
+type buffer struct {
+	*bytes.Buffer
+}
+
+func (b *buffer) Close() error {
+	b.Buffer.Reset()
+	return nil
+}
+
+func New(b *bytes.Buffer) *buffer {
+	if b == nil {
+		b = bytes.NewBuffer(nil)
+	}
+	return &buffer{b}
+}