<p dir="auto">Several clients have asked for support of send-to-sync notifications, where a notification is received and the device is expected to sync down the new data in the background in response to the notification (instead of the notification itself carrying the payload).</p>
<p dir="auto">My understanding from <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/collinjackson/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/collinjackson">@collinjackson</a> is that this is not currently possible to wire up due to lack of headless-Dart support in our APIs exposed to Flutter plugins.</p>
<p dir="auto">This issue tracks work in the engine. Providing APIs to access the engine support is tracked in <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="152639518" data-permission-text="Title is private" data-url="https://github.com/flutter/flutter/issues/3671" data-hovercard-type="issue" data-hovercard-url="/flutter/flutter/issues/3671/hovercard" href="https://github.com/flutter/flutter/issues/3671">#3671</a></p>
<p dir="auto">When nesting a Slider widget in a Row the thumb shows up, but the text isn't rendered:</p>
<p dir="auto"><a target="_blank" rel="noopener noreferrer nofollow" href="https://user-images.githubusercontent.com/798935/37561408-9158165e-2a56-11e8-94b6-6558eea5ec18.png"><img src="https://user-images.githubusercontent.com/798935/37561408-9158165e-2a56-11e8-94b6-6558eea5ec18.png" alt="flutter_01" style="max-width: 100%;"></a></p>
<div class="highlight highlight-source-dart notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="Widget _buildLineControls() {
    return new Column(
      children: &lt;Widget&gt;[
        new Row(
          children: &lt;Widget&gt;[
            const Text('Line width:'),
            new Expanded(
              child: new Slider(
                min: 1.0,
                max: 15.0,
                divisions: 15,
                label: '${lineWidth.round()}',
                value: lineWidth,
                activeColor: lineColor,
                onChanged: onLineWidthChanged,
              ),
            ),
          ],
        ),
      ],
    );
  }"><pre class="notranslate"><span class="pl-c1">Widget</span> <span class="pl-en">_buildLineControls</span>() {
    <span class="pl-k">return</span> <span class="pl-k">new</span> <span class="pl-c1">Column</span>(
      children<span class="pl-k">:</span> <span class="pl-k">&lt;</span><span class="pl-c1">Widget</span><span class="pl-k">&gt;</span>[
        <span class="pl-k">new</span> <span class="pl-c1">Row</span>(
          children<span class="pl-k">:</span> <span class="pl-k">&lt;</span><span class="pl-c1">Widget</span><span class="pl-k">&gt;</span>[
            <span class="pl-k">const</span> <span class="pl-c1">Text</span>(<span class="pl-s">'Line width:'</span>),
            <span class="pl-k">new</span> <span class="pl-c1">Expanded</span>(
              child<span class="pl-k">:</span> <span class="pl-k">new</span> <span class="pl-c1">Slider</span>(
                min<span class="pl-k">:</span> <span class="pl-c1">1.0</span>,
                max<span class="pl-k">:</span> <span class="pl-c1">15.0</span>,
                divisions<span class="pl-k">:</span> <span class="pl-c1">15</span>,
                label<span class="pl-k">:</span> <span class="pl-s">'<span class="pl-s">${<span class="pl-v">lineWidth</span>.<span class="pl-en">round</span>()}</span>'</span>,
                value<span class="pl-k">:</span> lineWidth,
                activeColor<span class="pl-k">:</span> lineColor,
                onChanged<span class="pl-k">:</span> onLineWidthChanged,
              ),
            ),
          ],
        ),
      ],
    );
  }</pre></div>
<p dir="auto">But it works fine without the Row:</p>
<p dir="auto"><a target="_blank" rel="noopener noreferrer nofollow" href="https://user-images.githubusercontent.com/798935/37561421-cc897a7e-2a56-11e8-950b-1fe527c2d9f5.png"><img src="https://user-images.githubusercontent.com/798935/37561421-cc897a7e-2a56-11e8-950b-1fe527c2d9f5.png" alt="flutter_02" style="max-width: 100%;"></a></p>
<div class="highlight highlight-source-dart notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="Widget _buildLineControls() {
    return new Column(
      children: &lt;Widget&gt;[
               new Slider(
                min: 1.0,
                max: 15.0,
                divisions: 15,
                label: '${lineWidth.round()}',
                value: lineWidth,
                activeColor: lineColor,
                onChanged: onLineWidthChanged,
              ),
      ],
    );
  }"><pre class="notranslate"><span class="pl-c1">Widget</span> <span class="pl-en">_buildLineControls</span>() {
    <span class="pl-k">return</span> <span class="pl-k">new</span> <span class="pl-c1">Column</span>(
      children<span class="pl-k">:</span> <span class="pl-k">&lt;</span><span class="pl-c1">Widget</span><span class="pl-k">&gt;</span>[
               <span class="pl-k">new</span> <span class="pl-c1">Slider</span>(
                min<span class="pl-k">:</span> <span class="pl-c1">1.0</span>,
                max<span class="pl-k">:</span> <span class="pl-c1">15.0</span>,
                divisions<span class="pl-k">:</span> <span class="pl-c1">15</span>,
                label<span class="pl-k">:</span> <span class="pl-s">'<span class="pl-s">${<span class="pl-v">lineWidth</span>.<span class="pl-en">round</span>()}</span>'</span>,
                value<span class="pl-k">:</span> lineWidth,
                activeColor<span class="pl-k">:</span> lineColor,
                onChanged<span class="pl-k">:</span> onLineWidthChanged,
              ),
      ],
    );
  }</pre></div>
<p dir="auto">This is on the latest master version:</p>
<blockquote>
<p dir="auto">Doctor summary (to see all details, run flutter doctor -v):<br>
[✓] Flutter (Channel master, v0.2.3-pre.41, on Linux, locale en_US.UTF-8)<br>
[✓] Android toolchain - develop for Android devices (Android SDK 27.0.3)<br>
[✓] Android Studio (version 3.0)<br>
[✓] IntelliJ IDEA Community Edition (version 2017.2)<br>
[✓] VS Code (version 1.21.1)<br>
[✓] Connected devices (1 available)</p>
</blockquote>