How do I clear Datums from a caffe::Net in C++?

[Kevin]

I'm writing a loop that will input a large number of images as Datums into a Caffe Net. The heart of the loop is:

auto datumVector = CreateDatumVector();
float loss = 0.0;
dynamic_pointer_cast<caffe::MemoryDataLayer<float>>(net->layers()[0])->AddDatumVector(datumVector);
results = net->ForwardPrefilled(&loss);

How do I clear the Datum vector from the Net before each iteration?