Get socket reads and writes working with IOCP.

examples/echoserve.janet

@@ -0,0 +1,14 @@
+(defn handler
+  "Simple handler for connections."
+  [stream]
+  (defer (:close stream)
+    (def id (gensym))
+    (def b @"")
+    (print "Connection " id "!")
+    (while (:read stream 1024 b)
+      (printf " %v -> %v" id b)
+      (:write stream b)
+      (buffer/clear b))
+    (printf "Done %v!" id)))
+
+(net/server "127.0.0.1" "8000" handler)