Currently we have a single master process which can quickly become a bottleneck, so we want to be able to run multiple "master" nodes and scale horizontally.

Some notes:

• We have a concept of "streams" that are a sequence of items assigned a monotonically increasing ID, where there is a "max position" which guarentees that every item with an ID below that has been successfully persisted (even though some items with a higher ID may have been persisted).
• Replication between nodes is currently a fairly noddy TCP protocol where all nodes connect to the master process and get streamed updates. This approach will not work in a world where we have multiple "master" nodes.

Potential approaches:

• Move as much as possible onto workers, but retain a single "master" process that does nothing but orchestrate e.g. tracking max pos of streams, streaming updates to workers
• Use an external process, e.g. redis, rabbitmq, etc to manage these things for us.