This avoids accidental usage which could result in data being lost or
ignored (as only the last `user` in a single frame would arrive).
This was added specifically to debounce sample playback, but given that
it's only debouncing on a single frame (hardly noticeable) I'm not going
to add back support for that yet. It should be handled by sample
playback concurrency or something more local to the usage.
As it turns out, on some cultures, the "negative integer" sign is not
encoded using the U+002D HYPHEN-MINUS codepoint. For instance, Swedish
uses U+2212 MINUS SIGN instead. This was confusing the legacy decoder,
since it is correctly depending on the serialisation being
culture-independent.
To fix, ensure that the special "end replay" frame, as well as the
replay MD5 hash, are generated in a culture-invariant manner.
Thankfully the replay MD5 hash is currently being discarded in
`LegacyScoreDecoder`, so it changing in future scores should not have
any negative effect on lazer operation.