SITE_UNREACHABLE not handled by JGroupsTransport

Galder: @Dan Berindei @Pedro Ruivo @Bela Ban Any thoughts on my dev thread?

Galder: In essence, @Dan Berindei you made ChannelCallbacks implement UpHandler, but JChannel.invokeCallback() 
won't pass any events to receive instance variable because it doesn't check whether the receiver is UpHandler //cc @Tristan

Bela Ban: @Galder yes, this won't work

Bela Ban: @Galder You need to call RELAY2.setRouterStatusListener() directly

Bela Ban: Implementing this as part of Receiver won't help

Galder: Don't think RELAY2.setRouterStatusListener() is what I want - I can see RELAY2.handleMessage() passing up the 
stack Event.SITE_UNREACHABLE though, the problem is that there's no handler for that

Bela Ban: @Galder Yes, but the SITE_UNREACHABLE event is only handled by RequestCorrelator, not by JChannel

Galder: Ah ok, let me check what that does

Bela Ban: The thing is that RequestCorrelator is not used anymore (AFAIK), as Infinispan moved from 
MessageDispatcher to JChannel

Galder: the RequestCorrelator is never called

Galder: exactly

Bela Ban: So this is a regression caused by that move then

Galder: Yeah, that's my feeling too. That's why I was asking Dan about the move to make ChannelCallbacks class an 
UpHandler, because I noticed that happened when the move to JChannel happened

Galder: The impact of this is the following: if any site in SYNC and the site is unreachable, you'd get a timeout eventually 
instead of a immediate failure

Galder: I'm trying to implement auto x-site state transfer for protobuf metadata cache and I cannot do it until this is fixed

Galder: I'll see if I can get something working with ASYNC, but ASYNC is not a good option for protobuf metadata. 
If a node does not succesfully get it, it won't be able to work properly