* For a discussion of the signature of verifyNotNull, see the discussion above
   * Preconditions.checkNotNull.
   *
   * (verifyNotNull has many fewer "problem" callers, so we could try to be stricter. On the other
   * hand, verifyNotNull arguably has more reason to accept nullable arguments in the first
   * place....)
   */

  /**
   * Ensures that {@code reference} is non-null, throwing a {@code VerifyException} with a default

     * difference is that calling it with <Foo> won't work when an input Future has a @Nullable
     * type. So why even make that error possible by giving callers the choice?
     *
     * On the other hand, the current signature is consistent with the similar allAsList method. And
     * eventually this method may go away entirely in favor of an API like

bats eat cats?' for, you see, as she couldn't answer either
question, it didn't much matter which way she put it.  She felt
that she was dozing off, and had just begun to dream that she
was walking hand in hand with Dinah, and saying to her very
earnestly, `Now, Dinah, tell me the truth:  did you ever eat a
bat?' when suddenly, thump! thump! down she came upon a heap of
sticks and dry leaves, and the fall was over.

      fail("UnsupportedOperationException expected");
    } catch (UnsupportedOperationException expected) {
    }
    assertFalse(unmod.entries().contains(nefariousMapEntry("pwnd", 2)));
    assertFalse(unmod.keys().contains("pwnd"));
  }

  /**
   * The supplied multimap will be mutated and an unmodifiable instance used in its stead. The
   * multimap must support null keys and values.
   */

 * This communicates to your callers all of the semantic guarantees listed above, which is almost
 * always very useful information.
 *
 * <p>On the other hand, a <i>parameter</i> type of {@link ImmutableList} is generally a nuisance to
 * callers. Instead, accept {@link Iterable} and have your method or constructor body pass it to the
 * appropriate {@code copyOf} method itself.
 *

 * This communicates to your callers all of the semantic guarantees listed above, which is almost
 * always very useful information.
 *
 * <p>On the other hand, a <i>parameter</i> type of {@link ImmutableList} is generally a nuisance to
 * callers. Instead, accept {@link Iterable} and have your method or constructor body pass it to the
 * appropriate {@code copyOf} method itself.
 *

 *       contains all the right method <i>signatures</i> to implement {@link Iterable}, it does not
 *       actually do so, to avoid implying repeat-iterability.) {@code FluentIterable}, on the other
 *       hand, is multiple-use, and does implement {@link Iterable}.
 *   <li>Streams offer many features not found here, including {@code min/max}, {@code distinct},

   * description of the returned view's behavior.
   *
   * <p><b>Warning:</b> {@code Range}s always represent a range of values using the values' natural
   * ordering. {@code NavigableMap} on the other hand can specify a custom ordering via a {@link
   * Comparator}, which can violate the natural ordering. Using this method (or in general using

    // GWT's ConcurrentHashMap is a wrapper around HashMap, but it rejects null keys, which matches
    // the behaviour of the non-GWT implementation of newConcurrentHashSet().
    // On the other hand HashSet might be better for code size if apps aren't
    // already using Collections.newSetFromMap and ConcurrentHashMap.
    return Collections.newSetFromMap(new ConcurrentHashMap<E, Boolean>());
  }

      fail("UnsupportedOperationException expected");
    } catch (UnsupportedOperationException expected) {
    }
    assertFalse(unmod.entries().contains(nefariousMapEntry("pwnd", 2)));
    assertFalse(unmod.keys().contains("pwnd"));
  }

  /**
   * The supplied multimap will be mutated and an unmodifiable instance used in its stead. The
   * multimap must support null keys and values.
   */