src/vs/workbench/contrib/terminal/browser/terminalGroup.ts/SplitPane/constructor
class SplitPane:	constructor(
		readonly instance: ITerminalInstance,
		public orthogonalSize: number
	) {
		this.element = document.createElement('div');
		this.element.className = 'terminal-split-pane';
		this.instance.attachToElement(this.element);
	}