Store large events in memory

Storing the large events in memory allows checksum calculations to be done
in one step. This also makes the encryption of events easier as they
require the complete event in memory.

server/modules/routing/binlogrouter/blr_slave.c

@@ -3332,13 +3332,6 @@ blr_stop_slave(ROUTER_INSTANCE* router, ROUTER_SLAVE* slave)
         }
     }
 
-    /* Discard the queued residual data */
-    while (router->residual)
-    {
-        router->residual = gwbuf_consume(router->residual, GWBUF_LENGTH(router->residual));
-    }
-    router->residual = NULL;
-
     /* Now it is safe to unleash other threads on this router instance */
     router->reconnect_pending = 0;
     router->active_logs = 0;