GVFCMOM.Calculates the expected value of the Visual Fast Count method.
The function assumes that the count per segment is Negative Binomial with mean m/s and size k,
and that segment counts are independent. The expected value is also a function of the number of positives
d before segment counting is stopped.
expected.nb(k, m, s, d)expected.pois, GVFCMOM