src/vs/workbench/api/browser/mainThreadEditorTabs.ts/MainThreadEditorTabs/_generateTabId
class MainThreadEditorTabs:	private _generateTabId(editor: EditorInput, groupId: number) {
		let resourceString: string | undefined;
		// Properly get the resource and account for side by side editors
		const resource = EditorResourceAccessor.getOriginalUri(editor, { supportSideBySide: SideBySideEditor.BOTH });
		if (resource instanceof URI) {
			resourceString = resource.toString();
		} else {
			resourceString = `${resource?.primary?.toString()}-${resource?.secondary?.toString()}`;
		}
		return `${groupId}~${editor.editorId}-${editor.typeId}-${resourceString} `;
	}