'Add a record to a timeline.
Adding a record to a timeline also causes it to be added to the
schedule, if it is not already present.
If another record exists in the timeline with the same record key, it
will be overwritten.
The return value this function indicates whether or not the timeline is
ready for immediate digestion.'

def add(self, key, record, increment_delay=None, maximum_delay=None):

    raise NotImplementedError
