type Pool struct {
    local     unsafe.Pointer // local fixed-size per-P pool, actual type is [P]poolLocal
    localSize uintptr        // size of the local array

    victim     unsafe.Pointer // local from previous cycle
    victimSize uintptr        // size of victims array

    // New optionally specifies a function to generate
    // a value when Get would otherwise return nil.
    // It may not be changed concurrently with calls to Get.
    New func() any
}
func (p *Pool) Get() any  
func (p *Pool) Put(x any) 

package main

import (
    "fmt"
    "sync"
)

type Object struct {
    ID int
    // ...
}

func main() {
    // 1.創(chuàng)建一個(gè)sync.Pool對象
    pool := &sync.Pool{
       New: func() interface{} {
          fmt.Println("Creating a new object")
          return &Object{}
       },
    }
    // 2.pool.Get()方法從池中獲取一個(gè)對象。如果池中有可用的對象，Get()方法將返回其中一個(gè)；否則，它將返回一個(gè)新創(chuàng)建的對象
    obj := pool.Get().(*Object)
    // 3.操作對象
    obj.ID = 1
    // 4.調(diào)用pool.Put()方法將對象放回池中
    pool.Put(obj)
    objBar := pool.Get().(*Object)
    fmt.Println("Object ID:", objBar.ID)
}

package design_mode

import "fmt"

var chessPieceUnit = map[int]*ChessPiece{
	1: {
		Name:  "車",
		Color: "紅",
		PositionX: 1,
		PositionY: 11,
	},
	2: {
		Name:  "馬",
		Color: "黑",
		PositionX: 2,
		PositionY: 2,
	},
	// 其他棋子
}

func NewChessPieceUnitFactory() *ChessBoard {
	board := &ChessBoard{Cards: map[int]*ChessPiece{}}
	for id := range chessPieceUnit {
		board.Cards[id] = chessPieceUnit[id]
	}
	return board
}

pool := &sync.Pool{
    New: func() interface{} {
       fmt.Println("Creating a new object")
       return NewChessBoard()
    },
}

game1 := pool.Get().(*ChessBoard)
game2 := pool.Get().(*ChessBoard)
fmt.Println(game1)
fmt.Println(game2)
fmt.Println(game1.Cards[0] == game2.Cards[0]) 

type ChessBoard struct {
    Cards map[int]*ChessPiece
    Time  time.Time
} 

func main() {
    pool := &sync.Pool{
       New: func() interface{} {
          fmt.Println("Creating a new object")
          return NewChessBoard()
       },
    }
    var wg sync.WaitGroup
    for i := 0; i < 10; i++ {
       wg.Add(1)
       go func(id int) {
          defer wg.Done()
          obj := pool.Get().(*ChessBoard)
          obj.Time = time.Now()
          pool.Put(obj)
          fmt.Printf("Object ID: %v\n", obj.Time)
       }(i)
    }
    wg.Wait()
}