Publish the session's first bandwidth sample, once. The library downloads no
media, so the app's real media-driven measurement cannot be reproduced; the
app instead flips from the unmeasured sentinel to a measured value on the
feed phase (after the explore feed is fetched, the point where the capture's
first measured request follows). Flows call this at that navigation/phase
boundary; later calls are no-ops, keeping the published sample constant.
Publish the session's first bandwidth sample, once. The library downloads no media, so the app's real media-driven measurement cannot be reproduced; the app instead flips from the unmeasured sentinel to a measured value on the feed phase (after the explore feed is fetched, the point where the capture's first measured request follows). Flows call this at that navigation/phase boundary; later calls are no-ops, keeping the published sample constant.