Exchange is a test helper for the common pattern of trading messages with a proxy server over an open stream.

MustStartStream invokes StartStream, but fails `t` if the response does not contain a valid stream id.

NewAllowAllRPCAuthorizer generates a new authorizer which allows all RPCs to pass through.

NewRPCAuthorizer generates a new authorizer with the given policy.

PackStreamData creates a StreamData request for the supplied streamIds, with `req` as the payload.

StartStream establishes a new target stream through the proxy connection in `stream`.

StartTestDataServer will start the given server running (as a separate Go routine) and return the Listener to connect to it over.

StartTestDataServers will start N servers using StartTestDataServer returning a map of server -> Listener.

UnpackStreamData will unmarshal a StreamData entry into a slice of stream ids and the message associated with it.

WithBufDialer returns a DialOption which will lookup a bufnet connection in the map passed to it.

BufSize is the buffer size used for a bufnet listener.

EchoTestDataServer is a TestDataServiceServer for testing.