Through persistance systems, notably Divmod's Axiom project, i have been experimenting with the idea of asyncronous request of items which may or may not exist for some time. The idea is an abstraction of a terrible first idea for "persistant deferreds," which my very suggestion of lead to horrible responses over in #twisted, but well deserved, I now believe. The concept is similar but perhaps simplified for the limitations and complications involved. Operations may return an "asyncronous item," which in my implementation is done by an Item implementing the IAsyncronousOperation ("operation" may be replaced with "Item") interface. This is akin to returning a deferred. The item allows the caller to control the response to the availability of the item, but in a way that can survive server crashes and reboots, and is otherwise a persistant record, and not an emphemeral object. Borrowing additionally from Twisted, the asyncronous results can sup...