Debezium locking database durin bootstrap [DBZ-1240]

Migrated from [DBZ-1240](https://issues.redhat.com/browse/DBZ-1240)

We have a issue while running DBZ in distributed KC framework.

Here is the scenario. if have 3 KC servers running in a distributed mode.

KC1
KC2
KC3

Now we submit a config for bootstrapping. and while bootstrap is still not complete. if i try to add another server say KC4 to existing cluster this will create a lock on the DB it does looks like all the connectors try to get lock.

Lock will not be released untill i kill all KC process on all the servers. This causes drastic issues on database (mysql) as well.

Here is the database process list during that time.

{code}
| Id | User | Host | db | Command | Time | State | Info | Rows_sent | Rows_examined |
| 7603394 | debezium | 10.40.0.147:49502 | wepay | Query | 337 | Sending data | SELECT * FROM `***`.`**** ` | 166504738 | 0 |
| 7603674 | debezium | 10.40.255.52:54592 | NULL | Query | 186 | Waiting for table flush | FLUSH TABLES WITH READ LOCK | 0 | 0 |
| 7603804 | debezium | 10.40.1.46:46880 | NULL | Query | 118 | Waiting for table flush | FLUSH TABLES WITH READ LOCK | 0 | 0 |
| 7603805 | debezium | 10.40.1.46:46878 | NULL | Sleep | 118 | | NULL | 1 | 0 |
| 7603814 | debezium | 10.40.1.46:46934 | NULL | Binlog Dump GTID | 118 | Master has sent all binlog to slave; waiting for more updates | NULL
{code}

Start by reproducing the three-server KC bootstrap scenario, then add KC4 while bootstrap is still running and inspect the MySQL process list. Done means adding a server no longer leaves database locks or long-running FLUSH TABLES WITH READ LOCK queries that require killing all KC processes.

Written by the indexing model from the issue text.