src/vs/workbench/contrib/terminal/browser/terminalGroup.ts/TerminalGroup/split
class TerminalGroup:	split(shellLaunchConfig: IShellLaunchConfig): ITerminalInstance {
		const instance = this._terminalService.createInstance(shellLaunchConfig);
		this.addInstance(instance);
		this._setActiveInstance(instance);
		return instance;
	}