This fixes an issue where https://github.com/derekkraan/delta_crdt_ex/blob/master/lib/delta_crdt/causal_crdt.ex#L233 would constantly re-add a monitor for a node that is down each time the CRDT attempts to sync. This led to some strange behaviors where the CRDT ended up pretty much only handling DOWN messages and setting up new monitors.
This fixes an issue where
https://github.com/derekkraan/delta_crdt_ex/blob/master/lib/delta_crdt/causal_crdt.ex#L233would constantly re-add a monitor for a node that is down each time the CRDT attempts to sync. This led to some strange behaviors where the CRDT ended up pretty much only handlingDOWNmessages and setting up new monitors.