Ensures that the value read by the audio thread is well-defined. Bug: b/176104610 Change-Id: I15d1901522be79703b3dc188fbe03c752be09a60 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/212442 Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org> Reviewed-by: Per Åhgren <peah@webrtc.org> Commit-Queue: Gustaf Ullberg <gustaf@webrtc.org> Cr-Commit-Position: refs/heads/master@{#33503}