cause a var fault with given msg argument, i.e., call variant_fault.cause msg, i.e., use the current variant_fault effect to fail with the given message.
0.095dev (2025-10-09 18:01:25 GIT hash 4826e516431c193e428991dd546a46472973d8d4 built by fridi@fzen)
msg, i.e., use the current variant_fault effect to fail with the given message.