How to handle keyboard mic button event on iPhone

I have this UISearchBar sits on top of self.view. With the default keyboard shown when it became first responder, I wonder if there's any way to pick up a touch event of the microphone button. Any help would be greatly appreciated.

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Solution

You are viewing this microphone icon because your iPhone dictation is switched on under Settings>General>Keyboard>Dictation or Settings-->General-->Siri.

I think you can use text input mode to identify which input mode is currently going on.

UITextInputCurrentInputModeDidChangeNotification

Reference - https://developer.apple.com/documentation/uikit/uitextinputmode?language=objc