func Delay(delay time.Duration) Option {
	return func(c *Config) {
		c.delay = delay
	}
}
func Delay(delay time.Duration) Option {
	return func(c *Config) {
		c.delay = delay
	}
}
func Delay ( delay time . Duration ) Option { return func ( c * Config ) { c . delay = delay } }
// Delay set delay between retry
// default is 100ms
Delay set delay between retry default is 100ms