FLUSH removal causing state transfer timeouts

FLUSH removal (ISPN-83) is causing issues with state transfer as shown below. Vladimir, mind looking into it?

---------

This is something that happend to me when playing with hotrod servers.

I've built infinispan distribution from source (mvn install -P distribution -DskipTests=true)
unzipped infinispan-4.2.1.CR2-all.zip 2x to folders
distro1
distro2
created 2 virtual ifaces
192.168.11.101 test1
192.168.11.102 test2
ran

distro1/bin/startServer.sh -r hotrod -l test1 -c /home/mlinhard/dev/projects/infinispan/issues/infinispan.xml
distro2/bin/startServer.sh -r hotrod -l test2 -c /home/mlinhard/dev/projects/infinispan/issues/infinispan.xml

ran demo-hotrod-console
hotrodconsole-0.0.1-SNAPSHOT/bin/console.sh test1
entered
>put a a (which means put value "a" under key "a")
the servers waited a bit and then server 2 wrote some errors to stdout (I guess after some timeout expired)
client was still blocked, after some time produced
ERROR: Invalid magic number. Expected a1 and received 50

attaching

• binary version of demo-hotrod-console (source: https://github.com/mlinhard/demo-hotrod-console)
• server 2 stdout
• infinispan.xml

I tried this with 4.2.1.CR1 and it worked.