UISpin.swift

// previously defined or injected: counterSpin is the Spin that handles our counter rules
self.uiSpin = UISpin(spin: counterSpin)
// self.uiSpin is now able to handle UI side effects

// we now want to attach the UI Spin to the rendering function of the ViewController:
self.uiSpin.render(on: self, using: { $0.render(state:) })
// And once the view is ready (in “viewDidLoad” function for instance) let’s start the loop:
self.uiSpin.start()
// the underlying reactive stream will be disposed once the uiSpin will be deinit