src/vs/workbench/api/common/extHostDiagnostics.ts/DiagnosticCollection/_compareIndexedTuplesByUri
class DiagnosticCollection:	private static _compareIndexedTuplesByUri(a: [vscode.Uri, readonly vscode.Diagnostic[]], b: [vscode.Uri, readonly vscode.Diagnostic[]]): number {
		if (a[0].toString() < b[0].toString()) {
			return -1;
		} else if (a[0].toString() > b[0].toString()) {
			return 1;
		} else {
			return 0;
		}
	}