There is not reason to use an std::set for it since we don't care about
the ordering - only about the existance of a particular entry.
Hash table will be more efficient for this use case.
Signed-off-by: Vlad Zolotarov <vladz@scylladb.com>
Message-Id: <1528220892-5784-2-git-send-email-vladz@scylladb.com>