namespace BlazorBattles.Client.Services
{
    public class BananaService : IBananaService
    {
        private readonly HttpClient _http;

        public BananaService(HttpClient http)
        {
            _http = http;
        }

        public event Action OnChange;
        public int Bananas { get; set; } = 0;

        public void EatBananas(int amount)
        {
            Bananas -= amount;
            BananasChanged();
        }

        public async Task AddBananas(int amount)
        {
            var result = await _http.PutAsJsonAsync<int>("api/User/AddBananas", amount);
            Bananas = await result.Content.ReadFromJsonAsync<int>();
            BananasChanged();
        }

        void BananasChanged() => OnChange.Invoke();

        public async Task GetBananas()
        {
            Bananas = await _http.GetFromJsonAsync<int>("api/User/GetBananas");
            BananasChanged();
        }
    }
}



유데미 강의중 궁금한데 구글서치에서도 못찾것음


OnChange.Invoke();


이걸 왜쓰고 이게 하는역활이 정확히 뭐임?