src/vs/workbench/services/remote/common/remoteExplorerService.ts/TunnelModel/onTunnelClosed
class TunnelModel:	private async onTunnelClosed(address: { host: string; port: number }) {
		const key = makeAddress(address.host, address.port);
		if (this.forwarded.has(key)) {
			this.forwarded.delete(key);
			await this.storeForwarded();
			this._onClosePort.fire(address);
		}
	}