Gets the user's sending statistics.
The 'callback' parameter specifies a function which will be called when the operation completes (or an error is encountered). If the 'callback' parameter is not specified, then the method will block and will not return until the operation completes (or an error is encountered).
The callback for this method is defined as:
'err' is the error that occurred. If there was no error, then 'err' is 'null'.
'err' has 2 properties which hold detailed information:
This method gets the users sending statistics. The server will return a set of data points with information about the user's sending activity. Each data point represents a 15 minute interval of sending activity.
The following properties will be populated for each data point.