Because i simply want to get some LEDs blinking during a server call which isn't possible with the standard Ethernet library due to the blocking behavior of all its methods.
What ethernet functions do you see as blocking? The only blocking function would be client.write() if the tx buffer is full. It will wait for space in the buffer. AFAIK, nothing else is blocking, not even client.read() if nothing is in the rx buffer. It returns int -1 immediately.