// fetch data from the defined RRD
// using given consolidation function [default is AVERAGE],
// resolution (seconds, default is the RRD's stepping),
// start and end times (unix epoch, defaults are the RRD's last update time)
//
// fetch data from the defined RRD
// using given consolidation function [default is AVERAGE],
// resolution (seconds, default is the RRD's stepping),
// start and end times (unix epoch, defaults are the RRD's last update time)
//