code: public final void setNewVertexValue(VV newValue) {
  		if (setNewVertexValueCalled) {
  			throw new IllegalStateException("setNewVertexValue should only be called at most once per updateVertex");
  		}
  		setNewVertexValueCalled = true;
  
  		outVertex.f1 = newValue;
  
  		out.collect(Either.Left(outVertex));
  	}
docs: Sets the new value of this vertex.
  
  <p>This should be called at most once per ComputeFunction.
  
  @param newValue The new vertex value.