uasyncio.udp: Add example interacting with dnsmasq DNS.

uasyncio.udp/example_dns_junk.py

@@ -0,0 +1,26 @@
+# This example is intended to run with dnsmasq running on localhost
+# (Ubuntu comes configured like that by default). Dnsmasq, receiving
+# some junk, is still kind to reply something back, which we employ
+# here.
+import uasyncio
+import uasyncio.udp
+import usocket
+
+def udp_req(addr):
+    s = uasyncio.udp.socket()
+    print(s)
+    yield from uasyncio.udp.sendto(s, b"!eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee", addr)
+    try:
+        resp = yield from uasyncio.wait_for(uasyncio.udp.recv(s, 1024), 1)
+        print(resp)
+    except uasyncio.TimeoutError:
+        print("timed out")
+
+
+import logging
+logging.basicConfig(level=logging.INFO)
+
+addr = usocket.getaddrinfo("127.0.0.1", 53)[0][-1]
+loop = uasyncio.get_event_loop()
+loop.run_until_complete(udp_req(addr))
+loop.close()