I want to know how the aws step functions were implemented internally. If we tell the step function to wait for 10 sec, what will happen internally? and how it will callback exactly after 10 sec? That too at a large scale scheduling?
AWS Step Functions is non-open source service so you cannot find the internal workings until AWS open source it. AWS has introduced an open source service AWS Firecracker which essentially the technology that provides the foundation to AWS Lambda provisioning. An open source alternative to AWS Step Functions is Fission Workflows that might give you an idea how it internally works.