How to reference current TextField SwiftUI?

I have multiple CustomTextFields and when they are actively being edited I want to know which one is currently active. I have set tags but you can not reference the tag inside the onEditingChanged closure.

struct CustomTextField : View {
 
                 var placeHolderString : String
        @Binding var contentString.    : String

                    var body : some View {
     
                       TextField(placeHolderString, text: $contentString, onEditingChanged: { (editing) in     
                                      //Determin which TextField is currently active here                   
                       }, onCommit: {               
                      
                 }).textFieldStyle(RoundedBorderTextFieldStyle())
                   .multilineTextAlignment(.center)
       
                  }
   
 }