Is it possible to include a blocking operation in the main task queue?

It is not recommended to include a blocking operation in the main queue, especially in iOS development.

The main queue is responsible for updating the UI and handling user events. If a blocking operation (such as a long synchronous task or waiting) is performed on it, it will lead to:

• Interface freezing
• Loss of app responsiveness
• Poor user experience

The correct approach is to perform blocking or long-running operations in a background thread or queue, and update the UI back on the main queue.

Example of using GCD:

DispatchQueue.global(qos: .background).async {
    // Long operation
    let result = heavyCalculation()

    DispatchQueue.main.async {
        // UI update
        self.label.text = "Result: \(result)"
    }
}

Thus, the main queue remains free to handle the interface, while heavy tasks are executed asynchronously.