Get score of a certain bucket. At own risk.
Clear all counts, reset reference and update time.
Get a weighted sum score, weight for bucket i: w(i) = factor^i.
Set the value for a buckt.
Get score from start on, until before end, with factor.
Update without adding, also updates reference and update time. Detects time
Update and add (updates reference and update time).
Get the duration of a bucket in milliseconds.
Get the reference time for the transition from the first to the second bucket.
Get the last time when update was called (adding).
Get the number of buckets.