I have a multiple `mat-select` and would like to know if the `mat-option` that's been clicked has been selected or deselected. The `$event.target` object passed when the `(click)` is fired has no `selected` attribute I could use.

```html
<mat-form-field>
    <mat-select [formControl]="control" multiple>
        <mat-option 
          *ngFor="let option of options" 
          [value]="option"
          (click)="foo($event)"
        >
        {{ option }}
        </mat-option>
    </mat-select>
</mat-form-field>

```

```
public foo(event) {
    const hasBeenChecked = ???? // How do I know if my clicked option has been checked or unchecked?
}

```

Thanks in advance