From Avi:
This patchset introduces a linearization context for managed_bytes objects.
Within this context, any scattered managed_bytes (found only in lsa regions,
so limited to memtable and cache) are auto-linearized for the lifetime of
the context. This ensures that key and value lookups can use fast
contiguous iterators instead of using slow discontiguous iterators (or
crashing, as is the case now).
a921479e71