fn adoptable(stored: &[u8]) -> Result<Option<(&'_ UserId, &'_ DeviceId)>>Expand description
Reads a stored token value, yielding its owner only when the row is one this pass may annotate.
A foreign row omits the trailing expiry field and reads as None. This
server always writes that field, even empty, so every row it wrote encodes
shorter than it is stored. The length comparison is what skips a token issued
here after the import, whose foreign expiry no longer describes it.