util.concurrent, like nearly all our packages, has two .gwt.xml files: one
    for prod and one for tests. However, unlike our other packages, as of this
    writing it has test supersource but no prod supersource.

    GWT happens to use the prod .gwt.xml, so it looks for no supersource for
    tests, either. This causes it to fail to find AtomicLongMapTest.

    Our workaround is to tell GWT that util.concurrent and all other packages

    util.concurrent, like nearly all our packages, has two .gwt.xml files: one
    for prod and one for tests. However, unlike our other packages, as of this
    writing it has test supersource but no prod supersource.

    GWT happens to use the prod .gwt.xml, so it looks for no supersource for
    tests, either. This causes it to fail to find AtomicLongMapTest.

    Our workaround is to tell GWT that util.concurrent and all other packages

  }

  @Override
  public Collection<V> values() {
    return delegate.values();
  }

  @CanIgnoreReturnValue
  private <T> T checkValid(T t) {
    // a ClassCastException is what's supposed to happen!
    @SuppressWarnings("unchecked")
    K k = (K) t;
    int unused = comparator().compare(k, k);
    return t;
  }

  @Override
  public boolean equals(@Nullable Object obj) {

  }

  @Override
  public Collection<V> values() {
    return delegate.values();
  }

  @CanIgnoreReturnValue
  private <T> T checkValid(T t) {
    // a ClassCastException is what's supposed to happen!
    @SuppressWarnings("unchecked")
    K k = (K) t;
    int unused = comparator().compare(k, k);
    return t;
  }

  @Override
  public boolean equals(@Nullable Object obj) {

  /**
   * Creates a new ArrayBasedUnicodeEscaper instance with the given replacement map and specified
   * safe range. If {@code safeMax < safeMin} then no code points are considered safe.
   *
   * <p>If a code point has no mapped replacement then it is checked against the safe range. If it
   * lies outside that, then {@link #escapeUnsafe} is called, otherwise no escaping is performed.
   *

          Reflection.newProxy(Map.class, new CheckSetUpInvocationHandler(map, setUpRan));
      return proxy;
    }
  }

  /**
   * Intercepts calls to a {@code Map} to check that {@code setUpRan} is true when they happen. Then
   * forwards the calls to the underlying {@code Map}.
   */
  private static class CheckSetUpInvocationHandler implements InvocationHandler, Serializable {
    private final Map<String, String> map;

          Reflection.newProxy(Map.class, new CheckSetUpInvocationHandler(map, setUpRan));
      return proxy;
    }
  }

  /**
   * Intercepts calls to a {@code Map} to check that {@code setUpRan} is true when they happen. Then
   * forwards the calls to the underlying {@code Map}.
   */
  private static class CheckSetUpInvocationHandler implements InvocationHandler, Serializable {
    private final Map<String, String> map;

                getKeyForNullValue(),
                v3(),
                (oldV, newV) -> {
                  throw new AssertionFailedError(
                      "Should not call merge function if key was mapped to null");
                }));
    expectReplacement(entry(getKeyForNullValue(), v3()));
  }

  @MapFeature.Require({SUPPORTS_PUT, ALLOWS_NULL_KEYS})
  public void testMergeAbsentNullKey() {
    assertEquals(

        if (utf8Length != Utf8.encodedLength(sb)) {
          StringBuilder repro = new StringBuilder();
          for (int j = 0; j < sb.length(); j++) {
            repro.append(" ").append((int) sb.charAt(j)); // GWT compatible
          }
          assertEquals(repro.toString(), utf8Length, Utf8.encodedLength(sb));
        }
      }
    }
  }

 * newHasher().putByte(b1).putBytes(new byte[] { b2, b3 }).hash()
 * newHasher().putBytes(new byte[] { b1, b2, b3 }).hash()
 * }</pre>
 *
 * <p>If you wish to avoid this, you should either prepend or append the size of each chunk. Keep in
 * mind that when dealing with char sequences, the encoded form of two concatenated char sequences
 * is not equivalent to the concatenation of their encoded form. Therefore, {@link