ApplicationInstance

The ApplicationInstance encapsulates all of the stateful aspects of a running Application.

At a high-level, we break application boot into two distinct phases:

• Definition time, where all of the classes, templates, and other dependencies are loaded (typically in the browser).
• Run time, where we begin executing the application once everything has loaded.

Definition time can be expensive and only needs to happen once since it is an idempotent operation. For example, between test runs and FastBoot requests, the application stays the same. It is only the state that we want to reset.

That state is what the ApplicationInstance manages: it is responsible for creating the container that contains all application state, and disposing of it once the particular test run or FastBoot request has finished.