made sockets non-blocking

os.h

@@ -33,6 +33,9 @@ struct Address;
 typedef struct SocketHandle SocketHandle;
 struct SocketHandle;
 
+typedef struct ServerEvents ServerEvents;
+struct ServerEvents;
+
 typedef struct Socket Socket;
 struct Socket {
     const Address *address;
@@ -49,6 +52,7 @@ struct Server {
     SocketHandle *handle;
     SocketList clients;
     bool listening;
+    ServerEvents *events;
 };
 
 typedef struct ServerInitInfo ServerInitInfo;