This is a prototype for supporting warnings from field input nodes.
The warnings are added to the nodes that actually evaluate the fields,
since a single field input can be evaluated in both a proper and invalid context.
Warnings from multi-functions aren't supported-- only field inputs.
This doesn't work currently. The method also has a few big downsides:
1. Adding warnings isn't thread-safe
* A static mutex might be a fine way to address this, since warnings aren't a case to optimize for.
2. There might be duplicate messages from the `modify_geometry_sets` loops.
* This is a much harder problem since it's also a goal to avoid adding too much boilerplate code to every node.
* The warnings for each node could be stored in a set temporarily to avoid duplicates.
So, instead of using a callback, I suggest adding a temporary set container to `GeoNodeExecParams` and passing a reference to it.
When adding to the set, a static mutex could be locked.
{F12762695 size=full}