set state(state) {
        if (this._state === state) {
            return;
        }
        this.el.classList.toggle('disabled', state === 0 /* SashState.Disabled */);
        this.el.classList.toggle('minimum', state === 1 /* SashState.AtMinimum */);
        this.el.classList.toggle('maximum', state === 2 /* SashState.AtMaximum */);
        this._state = state;
        this.onDidEnablementChange.fire(state);
    }
The state of a sash defines whether it can be interacted with by the user
as well as what mouse cursor to use, when hovered.