Non blocking receive

def nonblock_recv(self):
        """Non blocking receive"""

        if self.buffered_frames():
            # Get a frame from the buffer
            return self.get_frame()

        # Set the non blocking flag, read from the socket, and unset the flag
        self.set_nonblock(True)
        pkt = L2bpfListenSocket.recv(self)
        self.set_nonblock(False)
        return pkt