If config.url is provided it is returned as-is. Otherwise the URL is
derived from the current page location using the convention
WS port = HTTP port + DEFAULT_WS_PORT_OFFSET (HTTP 8080 -> WS 8082; port+1
is skipped to avoid Metro's 8081). Returns null when no URL can be
determined (no explicit URL and no location available).
Resolve the WebSocket URL to connect to.
If
config.urlis provided it is returned as-is. Otherwise the URL is derived from the current page location using the conventionWS port = HTTP port + DEFAULT_WS_PORT_OFFSET(HTTP 8080 -> WS 8082; port+1 is skipped to avoid Metro's 8081). Returnsnullwhen no URL can be determined (no explicit URL and no location available).