Clarify in CONTRIBUTING guide whether the spec should be trying to handle users passing incorrect argument types or client receiving malformed messages from realtime #374
Description
Regarding "malformed" messages - this is different from "robustness principle" expressed in https://sdk.ably.com/builds/ably/specification/main/features/#RSF1 - which only mentions "unrecognised attributes or enum values". We should also decide if we want the spec to handle cases where messages have missing fields or where "recognised" fields have incorrect type/do not make sense in the current context (e.g. mismatched objectIds in Object messages).