Adds the value to the current pending data.
- iOS 8.0+
- macOS 10.10+
- Mac Catalyst 13.0+Beta
- tvOS 9.0+
- watchOS 2.0+
- Xcode 8.0+
The value you want to add the dispatch source.
After you call this method, the dispatch source submits its event handler to its target queue to process the data. If you specify
0 for the data parameter, the dispatch source does not submit its event hander for execution.