Clarify the stateful nature of channels #1660
Description
The API part of the Standard could be a lot clearer about whats expected of a Channel implementation regarding its stateful nature, i.e. that a Channel retains the most recent context of each type (and after #1290 is resolved, its metadata). A clarification would be useful at the start of the Context Channels section and Channel API reference page
At present, we're only clear about the stateful nature of channels in the addContextListener and getCurrentContext references - which is far too late!
Any clarification added will need updating when resolving #1646 and the metadata additions in #1290 as more detail will need to be retained, such as the timestamps of messages and other metadata.
Original conversation #1646