Sets the receiver as the current progress object of the current thread and specifies the portion of work to be performed by the next child progress object of the receiver.
- iOS 7.0+
- macOS 10.9+
- Mac Catalyst 13.0+Beta
- tvOS 9.0+
- watchOS 2.0+
The number of units of work to be carried out by the next progress object that is initialized by invoking the
init(parent:method in the current thread with the receiver set as the parent. This number represents the portion of work to be performed in relation to the total number of units of work to be performed by the receiver (represented by the value of the receiver’s
totalproperty). The units of work represented by this parameter must be the same units of work that are used in the receiver’s
Use this method to build a tree of progress objects, as described in Creating a Tree of Progress Objects.