Update.

test/udp/send_receive.wren

@@ -0,0 +1,30 @@
+// retoor <retoor@molodetz.nl>
+
+import "udp" for UdpSocket
+import "timer" for Timer
+import "scheduler" for Scheduler
+
+var server = UdpSocket.new()
+server.bind("127.0.0.1", 0)
+var serverPort = server.localPort
+
+var received = null
+
+Scheduler.add {
+    received = server.receive()
+    server.close()
+}
+
+var client = UdpSocket.new()
+client.bind("127.0.0.1", 0)
+
+Timer.immediate {
+    client.send("test", "127.0.0.1", serverPort)
+    client.close()
+}
+
+Timer.sleep(100)
+
+System.print(received != null) // expect: true
+System.print(received[0]) // expect: test
+System.print(received[1]) // expect: 127.0.0.1