For more information see https://sendgrid.com/docs/API_Reference/Web_API_v3/index.html
SendGrid::SendGridClient sgc
SendGrid::SendGridMessage msg;
msg.setSubject("QtSendGrid Test");
msg.setFrom( new SendGrid::EmailAddress {"[email protected]", "Example.com"});
msg.AddContent(SendGrid::SendGridMimeType::Html, ...);
msg.AddContent(SendGrid::SendGridMimeType::Text, ...);
SendGrid::Personalization p;
p.to.append( SendGrid::EmailAddress{"[email protected]"});
p.cc.append({"[email protected]"});
msg.addPersonalization(p);
sgc.sendEmail(msg);