self-defined boundary conditions

[HarondFinch]

Wonderful work here, greatly appreciate the contributions made by the authors!
JAX-Fluids is now a well-developed package, yet l find that the default classes of boundary conditions are not suitable for my applications. l am creating a combustor simulation with an injection boundary condition, this boundary condition is more like the Velocity-Inlet boundary conditions in Ansys Fluent, where l take the extrapolated pressure as the pressure in halo grids, but the velocity and tempreature in halo grids are given by user-defined values (they could be functions of extrapolated pressure). By applying this boundary conditions, the injection speed can adapt to the pressure in the combustor.
In order to do that, do l need to write a self-defined boundary condition as a new class? How should l integrate this class to your coding framework? l'll appreciate it so much if you could enlight me a little. Looking forward to your reply!