This is useful because some platform have rather slow audio stream initialization time, especially the first time an audio stream is created for the process. We put in telemetry probes to measure that: First stream opened for the process: http://telemetry.mozilla.org/#filter=nightly%2F33%2FAUDIOSTREAM_FIRST_OPEN_MS&aggregates=multiselect-all!Submissions!Mean!5th%20percentile!25th%20percentile!median!75th%20percentile!95th%20percentile&evoOver=Builds&locked=true&sanitize=true&renderhistogram=Graph Subsequent streams: http://telemetry.mozilla.org/#filter=nightly%2F33%2FAUDIOSTREAM_LATER_OPEN_MS&aggregates=multiselect-all!Submissions!Mean!5th%20percentile!25th%20percentile!median!75th%20percentile!95th%20percentile&evoOver=Builds&locked=true&sanitize=true&renderhistogram=Graph