code: public static TagValue create(String value) {
      Utils.checkArgument(isValid(value), "Invalid TagValue: %s", value);
      return new AutoValue_TagValue(value);
    }
docs: Constructs a {@code TagValue} from the given string. The string must meet the following
  requirements:
  
  <ol>
  <li>It cannot be longer than {@link #MAX_LENGTH}.
  <li>It can only contain printable ASCII characters.
  </ol>
  
  @param value the tag value.
  @throws IllegalArgumentException if the {@code String} is not valid.
  @since 0.8