You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: pool_test.go
    path of file: ./repos/go101/pages/optimizations/code/0.2-memory-allocations/-use-pool-to-reduce-allocations
    
    the code of the file until where you have to start completion: package main

import "sync"
import "testing"

func Benchmark_Slice(b *testing.B) {
	var pool = sync.Pool{
		New: func() interface{} {
			return make([]by
    
func Benchmark_CustomPool_Synced(b *testing.B) {
	type Node struct {
		s []byte
		n *Node
	}
	var m sync.Mutex
	var head *Node
	var Get = func() *Node {
		m.Lock()
		defer m.Unlock()
		if head == nil {
			return &Node{
				s: make([]byte, 256),
			}
		}
		n := head
		head = head.n
		return n
	}
	var Put = func(n *Node) {
		m.Lock()
		defer m.Unlock()
		n.n = head
		head = n
	}
	var bs []byte
	b.ResetTimer()
	
	for i := 0; i < b.N; i++ {
		node := Get()
		bs = node.s
		bs[0] = 123
		Put(node)
	}
}