  The accurate simulation of real--time quantum transport is notoriously
difficult, requiring a consistent scheme to treat incoming and outgoing fluxes
at the boundary of an open system. We demonstrate a method to converge
non--equilibrium steady states using non--Hermitian source and sink potentials
alongside the application of dynamic density constraints during wavefunction
propagation. This scheme adds negligible cost to existing computational methods
while exhibiting exceptional stability and numerical accuracy.
