aggregation: allow interval between each points to be deferent of interval taked to calculate the aggregation

[clavay]

Example:

An index have one point each day at 00:00:00.

I want to aggregate the data making the difference between each day.
As a result, I want one point each day.

The current aggregation of one day, if started at 00:00:00, will take points for each day between 00:00:00 and 23:59:59.
It will find only one point and the difference will result in 0.

Solution:
Allow to specify a different range of time to take the values from the range between each aggregated point.
How:

• set an offset in second before the time range start and another offset after the time range ends. In our example, a positive offset of one second at the end of the time range should allow to get the index point of the next day.
• another solution ?