mail.ErrHeaderNotPresent
var ErrHeaderNotPresent = errors.New("mail: header not in message")
mail.ParseAddress
// ParseAddress parses a single RFC 5322 address, e.g. "Barry Gibbs <bg@example.com>"
func ParseAddress(address string) (*Address, error)
mail.ParseAddressList
// ParseAddressList parses the given string as a list of addresses.
func ParseAddressList(list string) ([]*Address, error)
mail.ParseDate
// ParseDate parses an RFC 5322 date string.
func ParseDate(date string) (time.Time, error)
mail.ReadMessage
// ReadMessage reads a message from r.
// The headers are parsed, and the body of the message will be available
// for reading from msg.Body.
func ReadMessage(r io.Reader) (msg *Message, err error)