A valid sequence of calls to the methods of an IterationObserver
represents an iteration. A valid sequence consists of any number of calls
to updateState with the successive non-final values, followed by a
final call to either finish with a successful completion value
or fail with the alleged reason for failure. After at most one
terminating calls, no further calls to these methods are valid and must be
rejected.
A valid sequence of calls to the methods of an
IterationObserverrepresents an iteration. A valid sequence consists of any number of calls toupdateStatewith the successive non-final values, followed by a final call to eitherfinishwith a successfulcompletionvalue orfailwith the allegedreasonfor failure. After at most one terminating calls, no further calls to these methods are valid and must be rejected.