sender

type Mail struct {
	// To is the email address of the recipient
	To string `json:"to" validate:"email,nonzero,max=256"`

	// ToName is optional and represents the recipeient's name
	ToName string `json:"toName,omitempty" validate:"max=256"`

	// From is the email address of the sender
	From string `json:"from" validate:"email,nonzero,max=256"`

	// FromName is optional and represents the name of the sender
	FromName string `json:"fromName,omitempty" validate:"max=256"`

	// Subject is the subject of the email
	Subject string `json:"subject" validate:"nonzero,max=998"` // RFC 5322 says not longer than 998

	// HTML is the HTML body of the email and is required unless Text is sent
	HTML string `json:"html,omitempty" validate:"max=2097152"` //2MB

	// Text is the plain-text body and is required unless HTML is sent
	Text string `json:"text,omitempty" validate:"max=2097152"` //2MB

	// ReplyTo is the Reply-To email address for the email
	ReplyTo string `json:"replyTo,omitempty" validate:"max=256"`

	// UniqueArgs are the SMTP unique arguments passed onto sendgrid
	// Note: pmStatsID is a reserved key and is used for stats recording
	UniqueArgs map[string]string `json:"uniqueArgs,omitempty" validate:"argsMap=max=256"`

	// Flags represent the category flags for this email and are used to
	// determine if the recipient has blocked this category of email
	Flags int64 `json:"flags"`

	// UniqueID is an optional uniqueID for this email that will be stored with
	// the email stats and can be used to later query when the last email with
	// this ID was sent
	UniqueID string `json:"uniqueID,omitempty" validate:"max=256"`
}