@NonNull
    @ParametersAreNonnullByDefault
    @SuppressWarnings("ConstantConditions")
    public static <S> TransmittableThreadLocal<S> withInitialAndCopier(Supplier<? extends S> supplier, TtlCopier<S> copierForChildValueAndCopy) {
        if (supplier == null) throw new NullPointerException("supplier is null");