Sorry I should have been more clear - I wants to find chats by the RECEIVER, not SENDER. I see in the API docs where I can pass the user_id to get all messages from a sender.
Perhaps a description of the use case will help:
Find all the chats for the CURRENT_USER since LAST_VIEWED_TIME. The idea is that I don't want to pull a large dataset (that will also need to be parsed) and I want to see all chat messages from other users since a given time to update a summary chat view as well as a specific hat view.
-p