sender

type Mail struct {
	To         string            `json:"to" validate:"email,nonzero,max=256"`
	ToName     string            `json:"toName,omitempty" validate:"max=256"`
	From       string            `json:"from" validate:"email,nonzero,max=256"`
	FromName   string            `json:"fromName,omitempty"	validate:"max=256"`
	Subject    string            `json:"subject" validate:"nonzero,max=998"`    // RFC 5322 says not longer than 998
	HTML       string            `json:"html,omitempty" validate:"max=2097152"` //2MB
	Text       string            `json:"text,omitempty" validate:"max=2097152"` //2MB
	ReplyTo    string            `json:"replyTo,omitempty" validate:"max=256"`
	UniqueArgs map[string]string `json:"uniqueArgs,omitempty" validate:"argsMap=max=256"`
	Flags      int64             `json:"flags"`
}