Explain the concept of a semantic tree and its application.

The Semantics Tree in Flutter is a data structure that describes the content and structure of the user interface from an accessibility perspective. It is used so that assistive technologies, such as screen readers, can correctly interpret and vocalize interface elements.

Each widget in Flutter can add semantic information, such as description, role (button, header), state (selected, disabled), etc. This information is collected into a tree that reflects the widget hierarchy.

Applications:

• Ensuring accessibility for people with disabilities.
• Testing the interface from an accessibility standpoint.
• Improving interaction with voice assistants and other assistive technologies.

Example: if you have a button with an icon, you can add a semantic description so that the screen reader vocalizes its purpose:

Semantics(
  label: 'Send message',
  child: IconButton(
    icon: Icon(Icons.send),
    onPressed: () {},
  ),
)