Use continuation bit in concurrent set

This refactors the concurrent set to examine and reserve a slot via CAS
with the hash, before then doing the same with the key.

This allows us to use an extra bit from the hash as a "continuation bit"
which marks whether we have ever probed past this key while inserting.
When that bit isn't set on deletion we can clear the field instead of
placing a tombstone.

0 files changed, 0 insertions, 0 deletions