       let bounds = range.split(separator: "-").map(String.init).flatMap(Int.init)
 #endif
       XCTAssertFalse(bounds.isEmpty)
-      headers["Content-Length"] = String(length-bounds[0])
-      headers["Range"] = nil
-      headers["If-Range"] = nil
-      headers["Content-Range"] = "bytes \(bounds[0])-\(length-1)/\(length)"
+      // let length = URLSessionResumeTests.largeLength
+      // headers["Content-Length"] = String(length-bounds[0])
+      // headers["Content-Range"] = "bytes \(bounds[0])-\(length-1)/\(length)"
+      // headers["Range"] = nil
+      // headers["If-Range"] = nil
       let response = HTTPURLResponse(url: largeURL, statusCode: 206, httpVersion: nil, headerFields: headers)!
       return ([.data(data[bounds[0]...])], response)
     }
     else
     {
-      headers["Content-Length"] = String(length)
-      headers["Accept-Ranges"] = "bytes"
+      // headers["Content-Length"] = String(URLSessionResumeTests.largeLength)
+      // headers["Accept-Ranges"] = "bytes"
       let formatter = DateFormatter()
       formatter.dateFormat = "E, d MMM yyyy HH:mm:ss z"
       formatter.timeZone = TimeZone(secondsFromGMT: 0)
       headers["Last-Modified"] = formatter.string(from: Date() - 100_000 )
+      let dumbCheckSum = data.reduce(0, { s, i in s &+ Int(i) })
+      headers["ETag"] = "\"" + String(dumbCheckSum, radix: 16) + "\""
       let cut = data.count/2 + 731
       let response = HTTPURLResponse(url: largeURL, statusCode: 200, httpVersion: nil, headerFields: headers)!
       return ([.data(data[0..<cut]), .wait(10.0), .data(data[cut...])], response)


    let (url, response) = try resumed.get()
    XCTAssertEqual(response.statusCode, 206)

    let f = try FileHandle(forReadingFrom: url)
    let d = f.readDataToEndOfFile()
    XCTAssertEqual(d.count, URLSessionResumeTests.largeLength)
#endif

    session.finishTasksAndInvalidate()

  static func largeGET(_ request: URLRequest) -> ([TestURLServer.Chunk], HTTPURLResponse)
  {
    XCTAssertEqual(request.url, largeURL)
    let data = URLSessionResumeTests.largeData
    var headers = request.allHTTPHeaderFields ?? [:]
    // headers.forEach { (key, string) in print("\(key): \(string)") }
    if var range = headers["Range"]
    {
      XCTAssert(range.starts(with: "bytes="))
