CSListSectionObserver

@available(OSX 10.12, *)
@objc
public protocol CSListSectionObserver : CSListObjectObserver

Implement the CSListSectionObserver protocol to observe changes to a list’s section info. CSListSectionObservers may register themselves to a CSListMonitor‘s -addListSectionObserver: method:

CSListMonitor *monitor = [CSCoreStore
    monitorSectionedListFrom:[CSFrom entityClass:[MyPersonEntity class]]
    sectionBy:[CSSectionBy keyPath:@"age"]
    fetchClauses:@[[CSOrderBy sortDescriptor:[CSSortKey withKeyPath:@"lastName" ascending:YES]]]];
[monitor addListSectionObserver:self];