[Proposal] State method support in SISL environments

[jkterry1]

The state method can sensibly be supported in the SISL environments. However, due to the difficulty of adding it and how useful it would likely be, we have no intention of adding it ourselves at this time. We would welcome contributions for this though if anyone wants to add it.

[benblack769]

What would these even look like though? Is figuring out an appropriate state part of the project?

[jkterry1]

I think it's well defined for pursuit, but yes figuring it out for waterworld and multiwalker is part of the project.