We will implement [RFC-8887 - A JSON Meta Application Protocol (JMAP) Subprotocol for WebSocket](https://tools.ietf.org/html/rfc8887)
as a transport mechanism for PUSH notifications.
We will [generalize EventBus](0046-generalize-event-bus.md) in order to achieve an out-of-the box Publish-Subscribe
system for JMAP related events, that do not fit in the mailbox API.
We will implement listeners registered on the JMAP event bus for WebSocket clients in order to carry over state changes
to the client.
We expect clients using the PUSH to lead to a drastic performance enhancement, as less data needs to be transmitted upon
As mentioned in RFC-8887 the usage of webSockets allows other performance optimizations:
- Requests can easily be compressed, which is not doable over HTTP for most available implementation (HTTP request
compression is not ubiquitous).
- WebSockets being connected, authentication can be performed once, when establishing the connection. This can allow to
reduce the load, if needed, on authentication systems. It might ease the use for instance of custom OpenId connect
People deploying JMAP need to be aware that load-balancing webSockets requires session stickiness.