textInputContextIdentifier timing relative to UITextViewDelegate's textViewDidBeginEditing

I was trying to provide `textInputContextIdentifier` in my view controller whenever user starts editing a UITextView. However, I noticed `textInputContextIdentifier` is triggered a few times by `UITextView becomesFirstResponder` and before UITextViewDelegate's `textViewDidBeginEditing:` callback, where the context identifier is determined based on the UITextView's properties. Is this by design that the text input context identifier has to be available before `textViewDidBeginEditing:` callback? Or is there any way to trigger `textInputContextIdentifier` when it is calculated in UITextViewDelegate's `textViewDidBeginEditing:` or anytime that it could change? I wasn't able to find much information elsewhere, thanks in advance!