They didn't read the code well enough.
When doing a Get (or taking a snapshot), the code calls the
LastSequence() method of the version set to get a version number. Reads
will ignore anything after this number.
Writers set this number only after making every element in a write batch
visible. This guarantees the reader will atomically see all of the
write batch or none of it. While every element in a write batch will
not necessarily have the same sequence number, a reader will not be able
to observe a version that splits the write batch.
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