as fast as possible
If your campaign objective is to deliver a rather complicated message, sometimes we use sequential messaging to deliver it in little pieces, one at a time. Through traditional media, these would be delivered sequentially over time assuming everyone consumes media similarly. For example, creative one would run for one or two weeks in print or television, followed by creative two for a similar period after that.
As you are undoubtedly aware, ad servers used to deliver online display campaigns come with many options and possibilities. One of the options is the pacing of the campaign. You can either set it to deliver evenly, or as fast as possible.