title: The argument type 'Future<List<User>>' can't be assigned to the parameter type 'Future<void> Function()' in onRefresh when using RefreshIndicator
body: <p>I am having a <strong>Future</strong> that is fetching and populating users below</p>
  <pre><code>Future&lt;List&lt;User&gt;&gt; _fetchUsersListUsingLoop() async {
      try {
        
        var response = await http.get(
            Uri.parse(
                &quot;https://api.json-generator.com/templates/Eh5AlPjYVv6C/data&quot;),
            headers: {
              &quot;Content-Type&quot;: &quot;application/json&quot;,
              &quot;Authorization&quot;: &quot;Bearer tltsp6dmnbif01jy9xfo9ssn4620u89xhuwcm5t3&quot;,
            });
  
  
        List&lt;User&gt; usersList = [];
  
        for (var u in json.decode(response.body)) {
          User user = User(u[&quot;email&quot;], u[&quot;about&quot;], u[&quot;name&quot;], u[&quot;picture&quot;],
              u[&quot;index&quot;], u[&quot;imageFetchType&quot;]);
  
          usersList.add(user);
        }
  
        return usersList;
      } catch (e) {
        log(&quot;FetchUsersListUsingLoopException $e&quot;);
  
        rethrow;
      }
    }
  
  </code></pre>
  <p>And below is how i am using <code>future</code> in <strong>FutureBuilder</strong> to call <code>_fetchUsersListUsingLoop()</code> and then use <strong>ListView.builder</strong> inside <strong>RefreshIndicator</strong> to show users in the <code>list</code></p>
  <pre><code>body: SizedBox(
          child: FutureBuilder(
              future: _fetchUsersListUsingLoop(),
              builder: (BuildContext context, AsyncSnapshot asyncSnapshot) {
                if (asyncSnapshot.data == null) {
                  return const Center(child: CircularProgressIndicator());
                } else {
                  return RefreshIndicator(
                    // background color
                      backgroundColor: Colors.white,
                      // refresh circular progress indicator color
                      color: Colors.green,
                      onRefresh: _fetchUsersListUsingLoop(),
                      child: ListView.builder(
                        itemCount: asyncSnapshot.data.length,
                        itemBuilder: (BuildContext context, int index) {
                          return ListTile(
                            contentPadding: const EdgeInsets.all(10),
                            leading: CircleAvatar(
                              backgroundImage:
                                  NetworkImage(asyncSnapshot.data[index].picture),
                            ),
                            title: Text(asyncSnapshot.data[index].name),
                            subtitle: Text(
                                &quot;${asyncSnapshot.data[index].email} \nUsing NetworkImage with backgroundImage&quot;),
                          );
                        },
                      ));
                }
              }),
        ),
  
  </code></pre>
  <p>I am getting <code>The argument type 'Future&lt;List&lt;User&gt;&gt;' can't be assigned to the parameter type 'Future&lt;void&gt; Function()'.</code> error in this line <code>onRefresh: _fetchUsersListUsingLoop(),</code> How can i be able to call <code>_fetchUsersListUsingLoop()</code> again when i swipe down to refresh</p>