email

var (
	ErrSMTPNoSet          = errors.New(`SMTP is not set`)
	ErrSenderNoSet        = errors.New(`The sender address is not set`)
	ErrRecipientNoSet     = errors.New(`The recipient address is not set`)
	ErrSendChannelTimeout = errors.New(`SendMail: The sending channel timed out`)

	//QueueSize 每批容量
	QueueSize = 50
	//QueueWait 队列等待时间
	QueueWait = time.Second * 30
)

var Callbacks = []func(*Config, error){}