Having trouble rereading a Lucene TokenStream

I am using Lucene 4.6, and am apparently unclear on how to reuse a TokenStream, because I get the exception:

java.lang.IllegalStateException: TokenStream contract violation: reset()/close() call missing, reset() called multiple times, or subclass does not call super.reset(). Please see Javadocs of TokenStream class for more information about the correct consuming workflow.

at the start of the second pass. I've read the Javadoc, but I'm still missing something. Here is a simple example that throws the above exception:

@Test
public void list() throws Exception {
  String text = "here are some words";
  TokenStream ts = new StandardTokenizer(Version.LUCENE_46, new StringReader(text));
  listTokens(ts);
  listTokens(ts);
}

public static void listTokens(TokenStream ts) throws Exception {
  CharTermAttribute termAtt = ts.addAttribute(CharTermAttribute.class);
  try {
    ts.reset();
    while (ts.incrementToken()) {
      System.out.println("token text: " + termAtt.toString());
    }
    ts.end();
  }
  finally {
    ts.close();
  }
}

I've tried not calling TokenStream.end() or TokenStream.close() thinking maybe they should only be called at the very end, but I get the same exception.

Can anyone offer a suggestion?