React router v4 route events

I'm new to react and previously I was using angular. Now I'm trying to build an app with react router v4. My current task sounds very simple: I want to add preloader and some authentication checkings for routes. In angular I would use events like 'routechangestart', 'routechangesucess' and resolve for authentication checking. However, I checked router documentation and I have't found none of this. Single option I saw is to use history.listen(), but it triggers only after route has changed. So my question is: how do I know when route starts changing, it has changed and what routes it were.

Here is how my router looks like (I want to handle this information in preloader component):

  ReactDOM.render(
    <Router>
      <Provider store={store}>
        <AppContainer>
          <div>
            <Preloader/>
            <Switch>
              <Route exact path="/" component={Header}/>
              <Route path="/app" component={App}/>
              <Route path="/content" component={Content}/>
              <Route path="*" component={Landing}/>
            </Switch>
          </div>

        </AppContainer>
      </Provider>
    </Router>,
    document.getElementById('main')
  );