in cxx/fbjni/detail/Exceptions.cpp [309:316]
local_ref<JThrowable> getJavaExceptionForCppBackTrace(const char* msg) {
local_ref<JThrowable> current =
msg ? JUnknownCppException::create(msg) : JUnknownCppException::create();
#ifndef FBJNI_NO_EXCEPTION_PTR
addCppStacktraceToJavaException(current, nullptr);
#endif
return current;
}