Map<Object, Object> sourceMap = new LinkedHashMap<>();
        for (Entry<?, ?> entry : entries) {
          if (sourceMap.put(entry.getKey(), entry.getValue()) != null) {
            throw new UnsupportedOperationException("duplicate key");
          }
        }
        return ImmutableBiMap.copyOf(sourceMap);
      }
    },
    COPY_OF_ENTRIES {
      @Override

        } else if (logger.isDebugEnabled()) {
            logger.debug("{} mapping exists.", index);
        }
    }

    protected Date getDateFromSource(final Map<String, Object> sourceMap, final String name) {
        final Object obj = sourceMap.get(name);
        if (obj instanceof Date) {
            return (Date) obj;
        }
        if (obj instanceof Number) {
            return new Date(((Number) obj).longValue());

  public static final String SET_COOKIE2 = "Set-Cookie2";

  /**
   * The HTTP <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/SourceMap">{@code
   * SourceMap}</a> header field name.
   *
   * @since 27.1
   */
  public static final String SOURCE_MAP = "SourceMap";

  /**
   * The HTTP <a href="https://github.com/WICG/nav-speculation/blob/main/opt-in.md">{@code