Call operator for objc.ObjCBlock<NSWindow? Function(ffi.Pointer<ffi.Void>, NSPopover)>.
objc.ObjCBlock<NSWindow? Function(ffi.Pointer<ffi.Void>, NSPopover)>
Available on ObjCBlock<NSWindow? Function(Pointer<Void>, NSPopover)>, provided by the ObjCBlock_NSWindow_ffiVoid_NSPopover_CallExtension extension