The original make_memtable used seastar::thread::yield() for
preemption, which required all callers to run inside a
seastar::thread context. This prevented the utilities from being
used directly in coroutines or parallel_for_each lambdas.
Make the primary functions — make_memtable, make_sstable_containing,
and verify_mutation — return future<> directly. Callers now .get()
explicitly when in seastar::thread context, or co_await when in
a coroutine.
make_memtable now uses coroutine::maybe_yield() instead of
seastar::thread::yield(). verify_mutation is converted to
coroutines as well.
Requested in:
https://github.com/scylladb/scylladb/pull/29416#pullrequestreview-4112296282
a4ebe16517