Use this attribute to indicate that a shared module constructor does not depend on any other module constructor being run first. This avoids errors on cyclic module constructors.

However, it is now up to the user to enforce safety. The module constructor must be marked @system as a result. Prefer to refactor the module constructor causing the cycle so it's in its own module if possible.

This is only allowed on shared static constructors, not thread-local module constructors.