probeOnceForTest property

  1. @visibleForTesting
set probeOnceForTest (Future<bool> fn())

Test-only seam (BEH-12, additive): inject the single-probe function so tests can drive the startup retry loop / confirmation without a real checker. A leading-underscore field is library-private and unsettable from an external test library; @visibleForTesting on a private member raises invalid_visibility_annotation, so a public setter is required (mirrors the existing handleVersionUpdateForTest / emitStartupStatusForTest seams).

Implementation

@visibleForTesting
set probeOnceForTest(Future<bool> Function() fn) => _probeOnce = fn;