fix (directchat): auto disconnect self once conn closed (#663)

When closing a connection of clientA(using the command “/disconnect”), the connection is then closed on clientA’s side. However, the connection remained open on clientB and clientB could continue sending message to clientA and clientA would receive those messages.

This PR listens for a closing connection on clientB, then also closes clientB’s connection.

examples/directchat.nim

@@ -79,7 +79,9 @@ proc handlePeer(c: Chat, conn: Connection) {.async.} =
       c.writeStdout $conn.peerId & ": " & $str
 
   except LPStreamEOFError:
-    c.writeStdout $conn.peerId & " disconnected"
+    defer: c.writeStdout $conn.peerId & " disconnected"
+    await c.conn.close()
+    c.connected = false
 
 proc dialPeer(c: Chat, address: string) {.async.} =
   # Parse and dial address
@@ -130,7 +132,7 @@ proc readLoop(c: Chat) {.async.} =
 
       await c.switch.stop()
       c.writeStdout "quitting..."
-      quit(0)
+      return
     else:
       if c.connected:
         await c.conn.writeLp(line)
@@ -189,5 +191,6 @@ proc main() {.async.} =
 
   await chat.readLoop()
   await allFuturesThrowing(libp2pFuts)
+  quit(0)
 
 waitFor(main())