src/vs/workbench/api/common/extHostStatusBar.ts/StatusBarMessage/setMessage
class StatusBarMessage:	setMessage(message: string): Disposable {
		const data: { message: string } = { message }; // use object to not confuse equal strings
		this._messages.unshift(data);
		this._update();

		return new Disposable(() => {
			const idx = this._messages.indexOf(data);
			if (idx >= 0) {
				this._messages.splice(idx, 1);
				this._update();
			}
		});
	}