Combine events with overlapping start/end dates.
stockpile_events(events, states = NULL, gap = 1L, id_var = "patient_id")Event file
Events of interest in the data. If NULL, assume all events are of interest.
Gap (in days) to apply in prescriptions of the same type. Useful when the gap should
only apply to link together identical states (if the allowable gap is to be applied universally, can be
added to end prior to using the function)
Group identifier in the data. Default is patient_id