Add `chunk` segmented data library.

common/chunkstream/chunkNodePool.go

Index: common/chunkstream/chunkNodePool.go
diff --git a/common/chunkstream/chunkNodePool.go b/common/chunkstream/chunkNodePool.go
new file mode 100644
index 0000000000000000000000000000000000000000..0ab1f1fc44f8d5eba757cbdeef84d1e6c58b2359
--- /dev/null
+++ b/common/chunkstream/chunkNodePool.go
@@ -0,0 +1,35 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package chunkstream
+
+import (
+	"sync"
+)
+
+var chunkNodePool = sync.Pool{
+	New: func() interface{} {
+		return &chunkNode{}
+	},
+}
+
+func newChunkNode(c Chunk) *chunkNode {
+	n := chunkNodePool.Get().(*chunkNode)
+	n.Chunk = c
+	return n
+}
+
+// chunkNode wraps a Chunk interface in a linked-list node.
+type chunkNode struct {
+	Chunk
+
+	next *chunkNode
+}
+
+func (n *chunkNode) release() {
+	n.Chunk.Release()
+	n.Chunk = nil
+	n.next = nil
+	chunkNodePool.Put(n)
+}