unfiltered.put("cat", 3);
    unfiltered.put("dog", 2);
    unfiltered.put("horse", 5);
    Map<String, Integer> filtered = Maps.filterEntries(unfiltered, CORRECT_LENGTH);
    assertEquals(ImmutableMap.of("cat", 3, "horse", 5), filtered);

    filtered.put("chicken", 7);
    assertEquals(ImmutableMap.of("cat", 3, "horse", 5, "chicken", 7), filtered);

    unfiltered.put("cat", 3);
    unfiltered.put("dog", 2);
    unfiltered.put("horse", 5);
    Map<String, Integer> filtered = Maps.filterEntries(unfiltered, CORRECT_LENGTH);
    assertEquals(ImmutableMap.of("cat", 3, "horse", 5), filtered);

    filtered.put("chicken", 7);
    assertEquals(ImmutableMap.of("cat", 3, "horse", 5, "chicken", 7), filtered);

        FLAGS[prefixFlag or frameFlag or FLAG_PADDED] =
          FLAGS[prefixFlag] + '|'.toString() + FLAGS[frameFlag] + "|PADDED"
      }
    }

    for (i in FLAGS.indices) { // Fill in holes with binary representation.
      if (FLAGS[i] == null) FLAGS[i] = BINARY[i]
    }
  }

  /**
   * Returns a human-readable representation of HTTP/2 frame headers.
   *
   * The format is:
   *