AVSTR — stream controllers and endpoints in browser-type scenario needed

Summary: This is related to the need to put stream controllers and
endpoints in a browser-type sceanario. In this scenario the
StreamEndPoint_A in the browser calls request_connection() on
StreamEndPoint_B on the server. Because the StreamEndPoint_B
is behind the firewall it must provide for all of the listen
addresses of flows and must also provide the information about
their direction and format. The StreamEndPoint_A in the browser
can then decide which of the flows it can connect to based on name
or directionality and format.