How to compute hessian

New to Flux!
I want to compute the gradient and hessian for this loss function.

loss(x,y) = -sum(y.*log.(model(x)) .- (1 .- y).*log.(1 .- model(x))) * 1 // size(y, 2)

where

model = Flux.Dense(in,out,σ)

And how do you access the final values for hessain and gradient once the training is over