Declaring async functions

An async function is a function whose body is marked with the async modifier.

Adding the async keyword to a function makes it return a Future. For example, consider this synchronous function, which returns a String:

If you change it to be an async function—for example, because a future implementation will be time consuming—the returned value is a Future:

Note that the function’s body doesn’t need to use the Future API. Dart creates the Future object if necessary. If your function doesn’t return a useful value, make its return type Future<void>.