code: func Start(t *types.TestConfig) (<-chan *result.LambdaResults, func()) {
  
  	var infra infrastructure.Infrastructure
  	if t.RunDocker {
  		infra = dockerinfra.New(t)
  	} else {
  		infra = awsinfra.New(t)
  	}
  	teardown, err := infra.Setup()
  	HandleErr(err)
  	t.Lambdas = numberOfLambdas(t.Concurrency, len(t.Regions))
  	infrastructure.InvokeLambdas(infra)
  
  	results := make(chan *result.LambdaResults)
  
  	go func() {
  		for result := range infrastructure.Aggregate(infra) {
  			results <- result
  		}
  		close(results)
  	}()
  
  	return results, teardown
  }
docs: // Start a test