Call operator for objc.ObjCBlock<objc.CGRect Function(ffi.Pointer<ffi.Void>)>.
objc.ObjCBlock<objc.CGRect Function(ffi.Pointer<ffi.Void>)>
Available on ObjCBlock<CGRect Function(Pointer<Void>)>, provided by the ObjCBlock_NSRect_ffiVoid_CallExtension extension