a json string describing what monitor data is desired. This is a list of triples separated by spaces of the form: type startposition maxnumber.

The type must be one of convergence profile sweptvar progress variations, displaytype, or a guide that was previously returned in a displaytype block.

The startposition is an integer that specifies where to start in the sequence of monitor data of that type. Each of these types is available in a list, ordered by time. For example, as the simulation goes on, data points are added to the internal list of convergence items. If the caller needs to incrementally update a display, it can repeatedly call this method with the startposition for each of the types given as the size of the list it has previously obtained and displayed, which ensures there will be no duplication and the returned data will be new each time.

The maxnumber, if greater than 0, is the limit on the number of new items returned for each type. If the caller is able to handle any number of returned values, it can be left at 0.