
   *
   * - "[user_expectation_type]" : Each Response, Animation, or Idle
   *    UE in the trace generates a time interval whose name is that of the UE,
   *    converted to lower case and with underscores in place of spaces.
   *    For instance, if there are three "Scroll Response" UEs in the trace,
   *    then there will be three "scroll_response" time intervals, so the
   *    histogram scroll_response:energy will contain three samples.
   *
   * Note that each time interval type only generates ONE o