A new option for diskless replication on the replica side.
After a network failure, the replica may need to perform a full sync.
The other option for diskless full sync is `swapdb`, but it uses twice
as much memory, temporarily. In situations where this is not acceptable,
and where losing data is acceptable, the `flush-before-load` can be
useful. If the full sync fails, the old data is lost though. Therefore,
the new option is marked as "dangerous".
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Signed-off-by: kronwerk <ca11e5e22g@gmail.com>
Signed-off-by: kronwerk <kronwerk@users.noreply.github.com>
Co-authored-by: kronwerk <ca11e5e22g@gmail.com>