an class="err">│</span>     <span class="err">│</span>   <span class="err">│</span> <span class="n">reduce</span>   <span class="err">┌──────────┐</span>            <span class="err">│</span>     <span class="err">│</span> <span class="n">onNext</span>      <span class="err">│</span>  <span class="err">┌────────┐</span>
                  <span class="err">│</span>     <span class="err">│</span>   <span class="err">└─────────▶�