code: function getEventType(inboundMessage) {
      let recipientAddresses = _.map(inboundMessage.recipients, 'email');
      let ccAddresses = _.map(inboundMessage.cc, 'email');
  
      if (_.max([recipientAddresses.indexOf(fuse.config.inbound_address),
                 recipientAddresses.indexOf(inboundMessage.to.email)]) >= 0) {
        return 'direct_email';
      }
      else if (_.max([ccAddresses.indexOf(fuse.config.inbound_address),
                      ccAddresses.indexOf(inboundMessage.to.email)]) >= 0) {
        return 'cc_email';
      }
      else {
        return 'bcc_email';
      }
    }
docs: returns a string with the event type of this message
  
  @param {InboundMessage} inboundMessage
  @returns {string} eventType