in cxx/fbjni/detail/Registration-inl.h [115:126]
static R dispatch(alias_ref<jhybrid> ref, Args&&... args) {
try {
// This is usually a noop, but if the hybrid object is a
// base class of other classes which register JNI methods,
// this will get the right type for the registered method.
auto cobj = static_cast<C*>(ref->cthis());
return (cobj->*method)(std::forward<Args>(args)...);
} catch (...) {
C::mapException(std::current_exception());
throw;
}
}