ScopedCloseable

Base for coordinators that launch coroutines into an owned child scope and implement AutoCloseable.

Ownership model

The constructor creates a SupervisorJob that is a child of the parent scope's job, so:

• A crashing child coroutine does not propagate to the caller's scope (supervisor boundary).

• Parent-scope cancellation still propagates down — ownJob is a structural child.

• Every scope.launch inside this class is automatically a child of ownJob; no manual job list is needed. Job-list drift (a launch that escapes close) is structurally impossible.

Close contract

close is idempotent — safe to call multiple times. On the first call it invokes onClose (subclass hook for cleanup work), then cancels ownJob, which cancels all child coroutines. Subsequent calls are no-ops.

Subclasses must launch all background coroutines into scope (not into the caller's scope). Launching into the caller's scope bypasses the ownership invariant.

Parameters