public static boolean isEncoded(String value, Charset charset) {
    for (byte b : value.getBytes(charset)) {
      if (!isUnreserved((char) b) && b != '%') {
        /* break if there are any unreserved character */
        return false;
      }
    }
    return PCT_ENCODED_PATTERN.matcher(value).find();
  }
Determines if the value is already pct-encoded.

@param value to check.
@return {@literal true} if the value is already pct-encoded
core/src/main/java/feign/template/UriUtils.java