If the server doesn’t return a CREATED response with a
status code of 201, then throw an exception.
(Even in the case of a “404 Not Found” server response,
throw an exception. Do not return null.
This is important when examining
the data in snapshot, as shown below.)

Hooray! Now you’ve got a function that sends the title to a
server to create an album.

4. Get a title from user input

Next, create a TextField to enter a title and
a ElevatedButton to send data to server.
Also define a TextEditingController to read the
user input from a TextField.

When the ElevatedButton is pressed, the _futureAlbum
is set to the value returned by createAlbum() method.

On pressing the Create Data button, make the network request,
which sends the data in the TextField to the server
as a POST request.
The Future, _futureAlbum, is used in the next step.