GM:OnEntityWaterLevelChanged
Description
Called when the Entity:WaterLevel of an entity is changed.
0 - The entity isn't in water.
1 - Slightly submerged (at least to the feet).
2 - The majority of the entity is submerged (at least to the waist).
3 - Completely submerged.
This hook can be considered a physics callback, so changing collision rules (Entity:SetSolidFlags) in it may lead to a crash!