src/vs/workbench/browser/parts/editor/editorGroupView.ts/EditorGroupView/doCloseEditorWithDirtyHandling
class EditorGroupView:	private async doCloseEditorWithDirtyHandling(editor: EditorInput | undefined = this.activeEditor || undefined, options?: ICloseEditorOptions): Promise<boolean> {
		if (!editor) {
			return false;
		}

		// Check for dirty and veto
		const veto = await this.handleDirtyClosing([editor]);
		if (veto) {
			return false;
		}

		// Do close
		this.doCloseEditor(editor, options?.preserveFocus ? false : undefined);

		return true;
	}