return unmodifiableOrNull(delegate.lowerEntry(key));
    }

    @Override
    public @Nullable K lowerKey(@ParametricNullness K key) {
      return delegate.lowerKey(key);
    }

    @Override
    public @Nullable Entry<K, V> floorEntry(@ParametricNullness K key) {
      return unmodifiableOrNull(delegate.floorEntry(key));
    }

    @Override