private static UnaryOperator<String> entryValidator(Consumer<String> validator) {
            requireNonNull(validator);
            return value -> {
                validator.accept(value);
                return value;
            };
        }
Parses the given raw query string, using the validator on all keys and non-null values.
vespajlib/src/main/java/ai/vespa/http/HttpURL.java