function createMessage(message) {
    const encoding = 'base64';
    const generateTextFromHTML = !message.forceTextContent;

    const addresses = getFromAddress(message.from, message.replyTo);

    return {
        ...message,
        ...addresses,
        generateTextFromHTML,
        encoding
    };
}
Decorates incoming message object wit    h nodemailer compatible fields.
For nodemailer 0.7.1 reference see - https://github.com/nodemailer/nodemailer/tree/da2f1d278f91b4262e940c0b37638e7027184b1d#e-mail-message-fields
@param {Object} message
@param {boolean} [message.forceTextContent] - force text content
@param {string} [message.from] - sender email address
@param {string} [message.replyTo]
@returns {Object}