[vtkusers] Behavior of Cxx/TestTemporalCacheSimple.cxx

[Henry Lehmann]

hello all,

implementing processing of temporal data, i am examining 
TestTemporalCacheSimple.cxx.
i noticed, that RequestData of the class vtkTemporalSphereSource is 
called for following time steps:

this->ActualTimeStep : 0
this->ActualTimeStep : 1
this->ActualTimeStep : 2
this->ActualTimeStep : 3
this->ActualTimeStep : 4
this->ActualTimeStep : 5
this->ActualTimeStep : 6
this->ActualTimeStep : 7
this->ActualTimeStep : 8
this->ActualTimeStep : 9
this->ActualTimeStep : 0

why is RequestData called a second time for time step 0?
shouldnt the temporaldatasetcache cache the result and shouldnt it be 
reused?
imagine a reader reading data from a file. this would mean time step 0 gets
read two times.

please correct me if i am wrong.

thanks in advance,
Henry