change comment

Author: andrewseguin

src/lib/core/data-table/data-table.ts

@@ -94,7 +94,9 @@ export class CdkTable<T> implements CollectionViewer {
   private _dataDiffer: IterableDiffer<T> = null;
 
   /**
-   * Tracking function that will be used to check the differences in data changes.
+   * Tracking function that will be used to check the differences in data changes. Used similarly
+   * to ngFor trackBy function. Optimize row operations by identifying a row based on its data
+   * relative to the function to know if a row should be added/removed/moved.
    * Accepts a function that takes two parameters, `index` and `item`.
    */
   @Input()