NSFileProviderPartialContentFetching
Support for fetching part of a file’s content.
Declaration
protocol NSFileProviderPartialContentFetching : NSObjectProtocolOverview
Adopt this protocol to let the system request only part of a file. Apps that read files provided by your extension can benefit from this feature, either by minimizing the amount of data your file provider needs to download, or by finishing the download quickly, freeing up the reading process.
For example, a photo app could read just the metadata from each picture in a large album, without having to completely download all the images. Alternatively, a video streaming app could begin playing the video before reading the whole file, reading chunks of data just before it needs them.