This is the same problem as if we were to process the message while partitioned and then crash I believe (we lose the lazy queue and at that point have no record of the message). This case should be covered by the hashtree work. Changing it to a call probably makes it a bit less likely but then means the metadata write path blocks on briefly broadcast for not much extra guarantee. 

Regarding local state, the local process is required to "deliver" the message first locally before calling broadcast. This ensures a future exchange will include the broadcast e.g.: https://github.com/basho/riak_core/pull/363/files#L5R272