We have to handle it in another way.

Instead just fill it in with all zeros.

inline functions. Clear pStubMsg->Offset in ComputeVariance since it
isn't set by ComputeConformanceOrVariance and so could be left filled
with garbage.

handle is independent of the binding handle used in the call that
unmarshaled it, so we should use RpcBindingCopy to make a copy of it
and then call RpcBindingFree later to free it.

ComputeVariance in NdrConformantVaryingStructBufferSize.