in src/main/scala/com/spotify/bdrc/pipeline/JoinLogs.scala [35:45]
def detectPlaySaveSequence(pair: Seq[(String, LogEvent)]): Option[String] = {
val Seq(first, second) = pair
if (
first._1 == "play" && second._1 == "save" && first._2.track == second._2.track &&
second._2.timestamp - first._2.timestamp <= gapDuration
) {
Some(first._2.track)
} else {
None
}
}