Added getter for section.

Author: ivanvorobei

Example Apps/SPDiffable.xcodeproj/project.xcworkspace/xcuserdata/ivanvorobei.xcuserdatad/UserInterfaceState.xcuserstate

@@ -124,6 +124,15 @@ open class SPDiffableCollectionDataSource: UICollectionViewDiffableDataSource<SP
         return itemIdentifier(for: indexPath)
     }
 
+    /**
+     SPDiffable: Get section by index.
+     */
+    public func section(for index: Int) -> SPDiffableSection? {
+        let snapshot = self.snapshot()
+        guard index < snapshot.sectionIdentifiers.count else { return nil }
+        return snapshot.sectionIdentifiers[index]
+    }
+    
     /**
      SPDiffable: Get index path for item by identifier.
      */