 accumulator function.</p>
<p><code>stream = Stream.scan(fn, accumulator, stream)</code></p>
<table>
<thead>
<tr>
<th>Argument</th>
<th>Type</th>
<th>Required</th>
<th>Description</th>
</tr>
</thead>
<tbody><tr>
<td><code>fn</code></td>
<td><code>(accumulator, value) -&gt; result | SKIP</code></td>
<td>Yes</td>
<td>A function that takes an accumulator and value parameter and returns a new accumulator value of the same type</td>
</tr>
<tr>
<td><code>accumulator</code></td>
<td><code>any</code></td>
<td>Yes</