Return Connect service response immediately if non-blocking mode set

In the current implementation of the Packet socket API, setting a socket to non-blocking mode does not affect the connect operation. Regardless of the setting of non-blocking mode,  the Connect Service response will be returned after success or failure establishing the connection.

However, according to the POSIX, when the non-blocking mode is enabled on a socket prior using the connect() api call, the function shall return status EINPROGRESS and process the connect action in background. (For details see https://pubs.opengroup.org/onlinepubs/009695399/functions/connect.html)