Characteristics
- A task has a stable ID.
- A task defines the function to run.
- A task can receive input from a caller or run.
- A task returns a result that the runner can record.
How tasks define background work targets.
A task defines background work. It is the target that a task run executes.
Tasks exist because some work should be named and reusable before it is run. A
task describes what background work does. A run records one durable execution of
that work.