Proximity Matrix of Random Forest

I want to know how to get the proximity matrix of random forest in Matlab. For random forest, I build the model through fitcensemble with bag method. The concept of proximity matrix is not complex. It is a N by N matrix for N data points. Element (i, j) of proximity matrix represents the number of trees x_i nad x_j end in the same leaf. The proximity usually is scaled with the total number of trees. I want to know how to extract related information within Matlab.