Transaction has been replaced with timer metric which is supposed to count time interval durations.
chrono: default time_duration, clock, time_point have been added.
counter: internal_stats have been changed to work with boost::accumulators
gauge: internal_stats have been changed to work with boost::accumulators
accumulators: moving_average accumulator has been added.
gauge: internal_stats have been edited (+moving_average, +extended_p_square_quantile).
gauge: internal_stats interface has been edited (static methods have been replaced with non-static ones).
counter: internal_stats use gauge metrics instead of raw boost::accumulators::accumulator_set.
internal: internal_metric has been removed.
timer: internal_stats have been removed (timer duration is its value now).
timer: duration field has been renamed to value.
timer: finish action has been renamed to stop.