public static <T> Maybe<T> defined(final T nullableValue) {
        return new Maybe<>(nullableValue);
    }
A container that may be empty, may contain null, or may contain a value.
Distinct from {@link java.util.Optional<T>}, since Optional cannot contain null.

@param <T>
streams/src/main/java/org/apache/kafka/streams/state/internals/Maybe.java