title: How to combine several futures into one in flutter
body: <p>I am making a shopping app. In the products i have given a few tabs of different types of products which are being received from the api. I want to add another tab of 'All' which displays all the products in all other tabs together. All the APIs are being called with id of each tab title and are identical in structure. Online i could find a few answers regarding future.wait but i don't think it will work in this case because they talk about completing one task after another which is what i want but i want to combine the results too. Basically, how to combine all of these identical futures into one single future to be passed into futurebuilder or is there a workaround to this problem?</p>
  <p>Edit:
  I am getting my List of futures like this:-</p>
  <pre><code>for (int i = 0;i &lt;Length;i++) {
  
  ProductsList.add(CollectionProductServices().getCategories(collectionModel.childPackages[i].id.toString()));
  
    }
  </code></pre>