a tweak.</p>

<p>Primary means it is displayed alongside with the tweak name in the list UI.</p>

<p>Each tweak list will maintain a reuse poll of primary view,
so a list with hundreds of tweaks will not initialize hundreds of primary views.</p>

<p>Every tweak must have a primary view.
The primary view is used for tweaking the value.
For example, <code>Bool</code> uses a switcher as its primary view.</p>

          </div>
        </section>

        <section class="section">
          <div class="section-c