Receives chat messages from the given room

• Receiving the history ($lookIntoFuture=0): The next $limit messages after $lastKnownMessageId will be returned. The new $lastKnownMessageId for the follow up query is available as X-Chat-Last-Given header.
• Looking into the future ($lookIntoFuture=1): If there are currently no messages the response will not be sent immediately. Instead, HTTP connection will be kept open waiting for new messages to arrive and, when they do, then the response will be sent. The connection will not be kept open indefinitely, though; the number of seconds to wait for new messages to arrive can be set using the timeout parameter; the default timeout is 30 seconds, maximum timeout is 60 seconds. If the timeout ends a successful but empty response will be sent. If messages have been returned (status=200) the new $lastKnownMessageId for the follow up query is available as X-Chat-Last-Given header. The limit specifies the maximum number of messages that will be returned, although the actual number of returned messages could be lower if some messages are not visible to the participant. Note that if none of the messages are visible to the participant the returned number of messages will be 0, yet the status will still be 200. Also note that X-Chat-Last-Given may reference a message not visible and thus not returned, but it should be used nevertheless as the $lastKnownMessageId for the follow-up query.