tweak setup() export style

src/idz/index.ts

@@ -1,7 +1,7 @@
 import { Socket } from "net";
 
 import { dispatch } from "./handler";
-import setup from "./setup";
+import { setup } from "./setup";
 import { World } from "./world";
 
 const world = new World();

src/idz/setup.ts

@@ -36,7 +36,7 @@ interface Session {
   };
 }
 
-export default function setup(socket: Socket): Session {
+export function setup(socket: Socket): Session {
   //
   // Construct and transmit setup message
   //