What is the purpose of child in Consumer Provider Flutter

Question

I have a question about Consumer, of Provider package, in Flutter. I don't understand the purpose of argument "child" in the builder of Consumer

Consumer<MyModel>(builder: (context, myModel, child) {
// doing stuff using myModel variable
});

I could not find any doc about it.

Answer 1

The child is any widget that doesn't need the data inside of the provider, so when the data gets updated, they don't get re-created since they don't need the data, rather they are passed as a reference to the builder.

    Consumer(
       builder: (context, myModel, child) {
       // child will refer to the MaterialButton provided as the child argument in the 
       // Consumer named parameter,
       // doing stuff using myModel variable
       }
       child: MaterialButton( 
              child: Text("Do some action"), 
              onPressed: () {
              // do some actions
    },),);

Since the MaterialButton doesn't need the state of the provider, but its in the descendant tree, there is no need to re-render that, so it gets passed back to the builder, to save memory and increase performance