call method
Implementation
objc.CGSize call(ffi.Pointer<ffi.Void> arg0) => ref.pointer.ref.invoke
.cast<
ffi.NativeFunction<objc.CGSize Function(ffi.Pointer<objc.ObjCBlockImpl> block, ffi.Pointer<ffi.Void> arg0)>
>()
.asFunction<objc.CGSize Function(ffi.Pointer<objc.ObjCBlockImpl>, ffi.Pointer<ffi.Void>)>()(ref.pointer, arg0);