text: console.log('Before')
  getUser(1,(user) => {
      console.log('User',user)
      getRepo(user.githubUsername, (repos) => {
          console.log('Repos',repos)
      })
  })
  console.log('After')
  
  function getUser(id,call){
      setTimeout(() =>{
          console.log('Reading a user from a database...')
          call({id: id, githubUsername: 'fahmi'})
      },2000)
  }
  
  function getRepo(username,call){
      setTimeout(() =>{
          console.log('Calling Github API...')
          call(['repo1','repo2','repo3'])
      },2000)
  }