We study the standard model of distributed optimization of a sum of functions
$F(z) = \sum_{i=1}^n f_i(z)$ where node $i$ in a network holds the function
$f_i(z)$. We consider a harsh network model characterized by asynchronous
updates, message delays, unpredictable message losses, and directed
communication among nodes. In this setting, we analyze a modification of the
Gradient-Push method for distributed optimization, assuming that (i) node $i$
is capable of generating gradients of its function $f_i(z)$ corrupted by
zero-mean bounded-support additive noise at each step, (ii) $F(z)$ is strongly
convex, and (iii) each $f_i(z)$ has Lipschitz gradients. We show that our
proposed method asymptotically performs as well as centralized gradient descent
that takes steps in the direction of the sum of the noisy gradients of all the
functions $f_1(x), \ldots, f_n(x)$ at each step.