This is the lwip no-os version of SO_REUSEADDR, which is set on all
listening sockets in the espressif port; do so here as well,
it makes running servers easier. The "address in use" error does
not occur.
My pings go out, and then they come back
```py
import os
import wifi
import ipaddress
wifi.radio.connect(os.getenv('WIFI_SSID'), os.getenv('WIFI_PASSWORD'))
ipv4 = ipaddress.ip_address("8.8.4.4")
print("Ping google.com: %f ms" % (wifi.radio.ping(ipv4)*1000))
```
Gregory Neverov
Scott Shawcroft
Jeff Epler