Default mini-batch size in the Fitrnet function

I have recently been using the fitrnet function from the Statistics and Machine learning toolbox in order to do regression. Although having used it for a while, I am not sure of the mini-batch size that is used when computing the gradient for training.

I have looked through the documentation for the fitrnet function but have not been able to find the answer. It does speak of iterations, but not the number of iterations per epoch.

Does anyone know where to get this information and if the function uses full-batchs, mini-batches or stochastic GD.