Cross-platform first responder handling without subclassing views or making custom ViewRepresentables in SwiftUI. Similar to FocusState but for iOS 13+
ResponderChain now publishes when it finds new tagged responders which means you can listen to .onChange(of: chain.availableResponders)
Note: It doesn't update when UIKit changes the canBecomeFirstResponder.
Introduced method swizzling to get updates on the firstResponder changing on iOS.
Added View.withResponderChainForCurrentWindow() so you can use ResponderChain in SwiftUI only apps