Tells the delegate that editing of the specified text view has begun.
- iOS 2.0+
- Mac Catalyst 13.0+
- tvOS 9.0+
The text view in which editing began.
Implementation of this method is optional. A text view sends this message to its delegate immediately after the user initiates editing in a text view and before any changes are actually made. You can use this method to set up any editing-related data structures and generally prepare your delegate to receive future editing messages.