We changed from using set_output_multiple(interpolate) because data would not necessarily continue to flow through properly. This meant that we needed to check the input size in the work function because if we cycle through the filters, we can sometimes consume more inputs than we've been given, which messes up the consume/produce and bookkeeping. It's likely that we can find a better form of the forecast function here that does not require checking both noutput_items and ninput_items[0] in the while loop.