internal CountCallsMethods(ViewModelSpy <TModel> parent, int position)
 {
     this.parent   = parent;
     this.position = position;
 }
 internal CountCallers(ViewModelSpy <TModel> parent)
 {
     this.parent = parent;
 }
 internal CountCallerMethods(ViewModelSpy <TModel> parent, int count)
 {
     this.parent = parent;
     this.count  = count;
 }