Large events are now processed in chuncks

The router->last_written is used to store the position where the last event was
written. The replication header is also stored in a separate structure in
the router which is used later when the last packet of a multi-packet event
arrives.

server/modules/routing/binlog/blr.c

@@ -498,6 +498,7 @@ char		task_name[BLRM_TASK_NAME_LEN+1] = "";
 	inst->binlog_position = 0;
 	inst->current_pos = 0;
 	inst->current_safe_event = 0;
+	inst->master_event_state = BLR_EVENT_DONE;
 
 	strcpy(inst->binlog_name, "");
 	strcpy(inst->prevbinlog, "");