in loader/stream_loader.go [321:336]
func (s *StreamLoad) toValidUTF8(b []byte) []byte {
invalid := []byte("\uFFFD")
buf := s.pool.Get().([]byte)
for len(b) > 0 {
r, size := utf8.DecodeRune(b)
if r == utf8.RuneError && size == 1 {
buf = append(buf, invalid...)
} else {
buf = append(buf, b[:size]...)
}
b = b[size:]
}
return buf
}