Asynchronous interaction with Dropbox (see Section 2.5.1) that allows the user interface to remain responsive is provided automatically by the DropBox iOS API.Methods such as [DBRestClient loadFile:intoPath:] are asynchronous and return immediately rather than when the requested action is completed. The developer implements event handers for [DBRestClient loadedFile: contentType: metadata:] and [DBRestClient loadFileFailedWithError:. One of these is called when the action is completed and displays the results to the user.