ESP8266 SPI WiFi Shield ("nice to have")

bilekj:
Fixed in commit GitHub - JiriBilek/WiFiSpi at 4d12b26c8c5e80786d972e845f90f7bb858427b0
Please get new version of master library and try again.

I am trying it out.
On my DUE I set up a client which connects to a server (my PC).
The Due is just waiting for PC to send data.

After some time I got the following error, just once, but the system is still running:

[espspi_proxy.h:329] W: Slave tx is not ready, status 0

I was not trying for time endurance, so I don't know exactly how long after last data exchange this happened, maybe 2 to 3 hours.

Any thoughts?