DittoAttachmentFetchEvent
A representation of the events that can occur in relation to an attachment fetch.
There are three different attachment fetch events: completed, progress, or deleted.
There will be at most one completed or deleted event per attachment fetch. There can be many
progress events delivered for each attachment fetch.
Updates relating to an attachment fetch are delivered by registering a DittoAttachmentFetcher
through a call to fetchAttachment on a DittoCollection instance.
DittoAttachmentFetchEvent Enumeration Reference