Configuring Trickle Feeds
You can configure a campaign so that new contacts are added to the corresponding Engage sub-campaign on an on-demand basis, rather than a single batch upload. You do this by clicking on the Campaigns tab and choosing Trickle Feed from the Engage List Type in your campaign record. Now, as you add campaign members to the campaign, they are transferred to your sub-campaign. Note that Salesforce sends this data using asynchronous calls so there might be a few seconds delay in the transfer.