Make tee filter also syncronously

Tee filter seems to work asynchronously. With a too high pace tee filter looses some statements.
It would be nice to make tee filter switchable to synchronous working as well so it works more reliable in certain scenarios:

• Simulate a Push Replication from a secure zone to a non-secure zone (vs. M/S replication).
• Copy production traffic to QA/testing system
• Testing/comparing an old and a new MariaDB server version
• Testing/comparing MySQL and MariaDB during a migration phase to MariaDB