mc:: trace:: TraceCursor
A cursor for navigating a trace.
The cursor is either at some trace position, or is in the “nowhere” state.
In the former case, there is a sequence of [
TraceEvent]s that happened at
Cursors are extensions of
TraceSteps that allow random trace access.
Return the current trace position.
Set the current trace position.
If the position is outside the valid range, the cursor is reset into the “nowhere” state.