Similar to AWS SAM (https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/serverless-sam-cli-using-invoke.html) or Google Cloud Functions Framework (https://cloud.google.com/functions/docs/functions-framework).

I.e. the ability to run functions locally. It's expensive and slow to have to run and test code in a stitch project remotely all the time even for small changes.