Updated docs

docs/Internals.md

@@ -15,6 +15,8 @@ one thread calling `mg_poll_server()`, `mg_set_option()` or any other function
 that take `struct mg_server *` parameter. Mongoose does not
 mutex-protect `struct mg_server *`, therefore the best practice is
 to call server management functions from the same thread (an IO thread).
+On a multi-core systems, many server instances can be created, sharing the
+same listening socket and managed by a separate thread (see [example](https://github.com/cesanta/mongoose/blob/master/examples/multi_threaded.c)).
 
 
 It is an error to pass and store `struct mg_connection *` pointers for