Don't call SetReactorAsFinished from the sample/insert callback if reactor is already finished.
Don't call SetReactorAsFinished from the sample/insert callback if reactor is already finished.

PiperOrigin-RevId: 383402070
Change-Id: I264b3b3068aeda3ebc3c07f6be21f54b658bd679

deepmind/reverb,deepmind/reverb,deepmind/reverb,deepmind/reverb