What do you mean by the stateful and stateless micro-services for Service Fabric?

Service Fabric enables the user to build applications that comprise micro services. Stateless micro-services (like protocol gateways and web proxies) don’t maintain a mutable state outside a request and its response from the service. Examples of a stateless service include Azure Cloud Services worker roles. Stateful micro-services (like user accounts, databases, devices, shopping carts, and queues) maintain a mutable, authoritative state beyond the request and its response, unlike Stateless Services. Today’s Internet-scale applications comprise a combination of stateless as well as stateful micro-services.