func (p MailBuilder) AddAttachment(b []byte, contentType string, fileName string) MailBuilder {
	part := NewPart(contentType)
	part.Content = b
	part.FileName = fileName
	part.Disposition = cdAttachment
	p.attachments = append(p.attachments, part)
	return p
}
func (p MailBuilder) AddAttachment(b []byte, contentType string, fileName string) MailBuilder {
	part := NewPart(contentType)
	part.Content = b
	part.FileName = fileName
	part.Disposition = cdAttachment
	p.attachments = append(p.attachments, part)
	return p
}
func ( p MailBuilder ) AddAttachment ( b [ ] byte , contentType string , fileName string ) MailBuilder { part := NewPart ( contentType ) part . Content = b part . FileName = fileName part . Disposition = cdAttachment p . attachments = append ( p . attachments , part ) return p }
// AddAttachment returns a copy of MailBuilder that includes the specified attachment.
AddAttachment returns a copy of MailBuilder that includes the specified attachment .