     barrier()
 
     // Verify that contents look good.
-    if tid == .Leader {
+    if tid == .Primary {
       expectEqual("abcdef", privateString)
     } else {
       expectEqual("abcghi", privateString)

  expectEqual(0, ret)

  let (createRet1, tid1) = _stdlib_pthread_create_block(
    nil, sliceConcurrentAppendThread, .Leader)
  let (createRet2, tid2) = _stdlib_pthread_create_block(
    nil, sliceConcurrentAppendThread, .Follower)

  expectEqual(0, createRet1)
  expectEqual(0, createRet2)

    barrier()

    // Append to the private string.
    if tid == .Primary {
      privateString.appendContentsOf("def")
    } else {
      privateString.appendContentsOf("ghi")
