title: How run flutter 'packages pub run build_runner build' with debug mode in intellij idea?
body: <p>I want to put break point on my generator code, but I don't know how to run the command on the debug mode. </p>
  
  <p>I wrote generator using <code>source_gen</code> and <code>build_runner</code></p>
  
  <pre><code>class MyGenerator extends GeneratorForAnnotation&lt;Todo&gt; {
    @override
    FutureOr&lt;String&gt; generateForAnnotatedElement(
        Element element, ConstantReader annotation, BuildStep buildStep) {
      return "// Hey! Annotation found!";
    }
  }
  </code></pre>