func Test1() int {
	result := 0
	defer func() {
		result++
	}()
	return result
}

func Test2() (result int) {
	defer func() {
		result++
	}()
	return
}

func Test3() (result int){
	defer func(result int) {
		result++
	}(result)
	result = 0
	return
}

// slice数据结构定义
type slice struct {
	array unsafe.Pointer
	len   int
	cap   int
}

func Slice1() []int {
	mp := make([]int , 0)
	defer func() {
		mp = append(mp, 2)
	}()
	mp = append(mp, 1)
	return mp
}

func Slice2() []int {
	mp := make([]int ,0, 2)
	defer func() {
		mp = append(mp, 2)
	}()
	mp = append(mp, 1)
	return mp
}

func Slice3() []int {
	mp := make([]int, 0, 2)
	defer func(mp []int) {
		mp = append(mp, 2)
	}(mp)
	mp = append(mp, 1)
	return mp
}

func Slice4() (mp []int) {
	mp = make([]int, 0)
	defer func() {
		mp = append(mp, 2)
	}()
	mp = append(mp, 1)
	return mp
}

func Slice5() (mp []int) {
	mp = make([]int, 0, 1)
	defer func() {
		mp = append(mp, 2)
		mp = append(mp, 3)
	}()
	mp = append(mp, 1)
	return
}

func RSlice2() []int {
	mp := make([]int ,0, 2)
	mp = append(mp, 1)
	ret := mp // 对返回结果赋值
	func() {
		mp = append(mp, 2)
	}()
	return ret
}

func RSlice5()(mp []int)  {
	mp = make([]int, 0, 1)
	mp = append(mp, 1)
	// 有名返回值，不会再重新赋值
	func() {
		mp = append(mp, 2)
		mp = append(mp, 3)
	}()
	return mp
}

// SaveUploadedFile uploads the form file to specific dst.
func (c *Context) SaveUploadedFile(file *multipart.FileHeader, dst string) error {
	src, err := file.Open()
	if err != nil {
		return err
	}
	defer src.Close()

	out, err := os.Create(dst)
	if err != nil {
		return err
	}
	defer out.Close()

	_, err = io.Copy(out, src)
	return err
}

func TestFileOpen(paths []string) {
    for _,path := range paths{
        file, err := os.Open(path)
		if err != nil {
			panic(err)
		}
		defer file.Close()
       // 业务处理...
    }
}

// RecoveryWithWriter returns a middleware for a given writer that recovers from any panics and writes a 500 if there was one.
func RecoveryWithWriter(out io.Writer) HandlerFunc {
	var logger *log.Logger
	if out != nil {
		logger = log.New(out, "\n\n\x1b[31m", log.LstdFlags)
	}
	return func(c *Context) {
		defer func() {
			if err := recover(); err != nil {
				// 日志记录等...
			}
		}()
		c.Next()
	}
}