Can someone explain the use of Dispose?

    string timeString = DateTime.Now.ToLongTimeString();
    Timer timer;
    int interval = 1000
    
    //On page init
    protected override void OnInitialized()
    {
        //callback every 1000 ms
        timer = new Timer(UpdatePage, null, 0, interval);


    }

    //Callback function
    void UpdatePage(object _)
    {
        
        timeString = DateTime.Now.ToLongTimeString();
        //Rerenders the page
        InvokeAsync(StateHasChanged);
    }

    public void Dispose()
    {
        //why?
        timer.Dispose();
    }