  We prove an identity that relates the q-Laplace transform of the height
function of a (higher spin inhomogeneous) stochastic six vertex model in a
quadrant on one side, and a multiplicative functional of a Macdonald measure on
the other. The identity is used to prove the GUE Tracy-Widom asymptotics for
two instances of the stochastic six vertex model via asymptotics analysis of
the corresponding Schur measures.
