Try using Count and GetCount, akin to GetPos and SetPos. Although perhaps GetPos should therefore be Pos?
It goes against our style somewhat, but has been successful in practice, to have a stream (or chan in this case) be the last parameter in functions taking chans -- if the chan is a temporarily constructed thing, it reads much cleaner to see ChanType0(params0,ChanType1(params1, DestChan))).