dotnet-daily-tips

056 - await vs Task.WhenAll

There’s a difference between calling await three times on some Task and collecting 3 tasks and calling Task.WhenAll.

In the first case each await will be called one by one, probably giving some time benefit of doing it async, but in the second case we call all 3 tasks together we can gain more.

So if you have few task to run consider awaiting them together with Task.WhenAll.

// ❌ Don't call await in sequence
var ingredients = await api.LoadIngredients();
var recipes = await api.LoadRecipes();
var menu = await api.LoadMenu();

// ✅ use Task.WhenAll to wait for all tasks to complete asynchronously
var ingredientsTask = api.LoadIngredients();
var recipesTask = api.LoadRecipes();
var menuTask = api.LoadMenu();
Task.WhenAll([ingredientsTask, recipesTask, menuTask]);