Notification of step completion in the target VM.
The step event
is generated immediately before the code at its location is executed;
thus, if the step is entering a new method (as might occur with
StepRequest.STEP_INTO)
the location of the event is the first instruction of the method.
When a step leaves a method, the location of the event will be the
first instruction after the call in the calling method; note that
this location may not be at a line boundary, even if
StepRequest.STEP_LINE
was used.