*
   * @param formal The type whose type variables or itself is mapped to other type(s). It's almost
   *     always a bug if {@code formal} isn't a type variable and contains no type variable. Make
   *     sure you are passing the two parameters in the right order.
   * @param actual The type that the formal type variable(s) are mapped to. It can be or contain yet
   *     other type variables, in which case these type variables will be further resolved if

 * worst case time complexity of O(N^2). You are extremely unlikely to hit this quadratic case on
 * randomly ordered data (the probability decreases faster than exponentially in N), but if you are
 * passing in unsanitized user data then a malicious user could force it. A light shuffle of the
 * data using an unpredictable seed should normally be enough to thwart this attack.
 *

   * in which case the signal is a no-op, and the bigger-picture signal is lost unless interrupted
   * threads take special action by participating in the signal-passing game.
   */

  /*
   * Timeout handling is intricate, especially given our ambitious goals:
   * - Avoid underflow and overflow of timeout values when specified timeouts are close to

again, and we won't talk about cats or dogs either, if you don't
like them!'  When the Mouse heard this, it turned round and swam
slowly back to her:  its face was quite pale (with passion, Alice
thought), and it said in a low trembling voice, `Let us get to
the shore, and then I'll tell you my history, and you'll
understand why it is I hate cats and dogs.'

 * void exampleBadCaller() {
 *   double d = sqrt(-1.0);
 * }
 * }</pre>
 *
 * <p>would be flagged as having called {@code sqrt()} with an illegal argument.
 *
 * <h3>Performance</h3>
 *
 * <p>Avoid passing message arguments that are expensive to compute; your code will always compute
 * them, even though they usually won't be needed. If you have such arguments, use the conventional
 * if/throw idiom instead.
 *

  }

  private void doClose(Closeable closeable, boolean swallowException) throws IOException {
    doClose(closeable, swallowException, !swallowException);
  }

  // Close the closeable using the Closeables, passing in the swallowException
  // parameter. expectThrown determines whether we expect an exception to
  // be thrown by Closeables.close;
  private void doClose(Closeable closeable, boolean swallowException, boolean expectThrown)

   * or extract a variable, and put the suppression on that. However, a local variable typically
   * doesn't work: Because nullness analyses typically infer the nullness of local variables,
   * there's no way to assign a {@code @Nullable T} to a field {@code T foo;} and instruct the
   * analysis that that means "plain {@code T}" rather than the inferred type {@code @Nullable T}.

  }

  /*
   * To avoid the need to call requireNonNull so much, we could consider more clever approaches,
   * such as:
   *
   * - Make checkOpen return the non-null `seq`. Then callers can assign that to a local variable or
   *   even back to `this.seq`. However, that may suggest that we're defending against concurrent
   *   mutation, which is not an actual risk because we use `synchronized`.

 * reasonable and it will be fine.
 *
 * <ul>
 *   <li>If checking whether the <i>caller</i> has violated your method or constructor's contract
 *       (such as by passing an invalid argument), use the utilities of the {@link Preconditions}
 *       class instead.
 *   <li>If checking an <i>impossible</i> condition (which <i>cannot</i> happen unless your own

  }

  public void testLimit_illegalArgument() {
    try {
      FluentIterable<String> unused =
          FluentIterable.from(Lists.newArrayList("a", "b", "c")).limit(-1);
      fail("Passing negative number to limit(...) method should throw IllegalArgumentException");
    } catch (IllegalArgumentException expected) {
    }
  }

  public void testIsEmpty() {