@Override
    public Void call() throws Exception {
      Stopwatch timeRun = duration != DEFAULT_DURATION ? Stopwatch.createStarted() : null;
      int numRuns = 0;

      do {
        numRuns++;
        callAndValidate();
      } while ((iterations != DEFAULT_ITERATIONS && numRuns < iterations) ||
          (duration != DEFAULT_DURATION
              && timeRun.elapsed(SECONDS) <= duration.getSeconds()));
      return null;
    }
Sets the expected result of running the thread to be a value matching the given value

@param expectedValue the value expected to be returned from the thread. The value must
       implement equals
@return this, the ConcurrentOperation (containing a callable) that has been set to repeat
geode-junit/src/main/java/org/apache/geode/test/junit/rules/ConcurrencyRule.java