App driver is a small framework that supports life cycle management of fidl components by implementing the fuchsia::modular::Lifecycle FIDL service.
There are three flavors of app driver: for generic components (AppDriver), for components that are run as Modules (ModuleDriver), and for components that are run as Agents (AgentDriver). Agents and Modules have additional facets at initialization in addition to the asynchronous teardown sequence that fuchsia::modular::Lifecycle imposes. See the .h files for details.