One of the biggest challenges for mobile cross-platform frameworks is how to achieve native performance and how to help developers create different kinds of features for different devices and platforms with as little effort as possible. In doing so, we need to keep in mind that UX should remain the same but with unique components that are specific for each particular platform (Android and iOS).
Although cross-platform frameworks (in most of these cases) can resolve platform-specific tasks, there is a certain number of tasks which, with custom platform-specific code, can be achieved only through native. The question is, how can those frameworks establish communication between the specific platform and application? The best example is the Flutter's Platform Channel.