question: private BinlogPosition findHeartbeat ( MaxwellReplicator r ) throws Exception { r . startReplicator ( ) ; for ( RowMap row = r . getRow ( ) ; row != null ; row = r . getRow ( ) ) { if ( Objects . equals ( r . getLastHeartbeatRead ( ) , recoveryInfo . heartbeat ) ) return row . getPosition ( ) ; } return null ; }
target:  try to find a given heartbeat value from the replicator.