public static String unescape(String value) {
        for (int i = 0; i < value.length(); i++) {
            final char c = value.charAt(i);
            if (c < ' ' || c >= '~' || (c == '%' && i + 2 < value.length())) {
                return doUnescape(value.getBytes(StandardCharsets.US_ASCII));
            }
        }
        return value;
    }
Unescape the provided ascii to a unicode {@link String}.
grpc-protocol/src/main/java/com/linecorp/armeria/common/grpc/protocol/StatusMessageEscaper.java