Optimize client RAM memory usage

The receiveMessage() function would regularly keep casting strings based
on a 2048 byte array, this didn't seemingly pose a problem until I
noticed the RAM usage go through the roof when the client had to be
populated with the chat history of a lengthy chat log by the server. To
fix this I am now creating a second array using the number of bytes
being returned by the Read() method and copying the 2048 byte array's
contents into it, setting the former array to nil afterwards.

cmd/clientFunc.go

@@ -72,12 +72,12 @@ func Client() {
 	defer conn.Close()
 	data.Server = conn
 
-	nameRequest, err := receiveMessage(conn)
+	nameRequest, b, err := receiveMessage(conn)
 	if err != nil {
 		log.Fatalf("Error occurred reading from server while requesting name: %v\n", err)
 	}
 	fmt.Print(nameRequest)
-	test := make([]byte, 2048)
+	test := make([]byte, b)
 	copy(test, "Password: ")
 
 	if nameRequest == string(test) {
@@ -87,7 +87,7 @@ func Client() {
 		}
 		conn.Write([]byte(pass))
 
-		nameRequest, err := receiveMessage(conn)
+		nameRequest, _, err := receiveMessage(conn)
 		if err != nil {
 			if err != io.EOF {
 				log.Fatalf("Error occurred reading from server while requesting name: %v\n", err)
@@ -113,7 +113,7 @@ func listenMessages(g *gocui.Gui) {
 		log.Panicln(err)
 	}
 	for {
-		messageFromServer, err := receiveMessage(data.Server)
+		messageFromServer, _, err := receiveMessage(data.Server)
 		if err != nil {
 			// What the hell is this
 			if err == gocui.ErrQuit {
@@ -130,13 +130,20 @@ func listenMessages(g *gocui.Gui) {
 	}
 }
 
-func receiveMessage(conn net.Conn) (s string, err error) {
+func receiveMessage(conn net.Conn) (s string, b int, err error) {
 	serverMessage := make([]byte, 2048)
-	if _, err := conn.Read(serverMessage); err != nil {
-		return "", err
+	n, err := conn.Read(serverMessage)
+	if err != nil {
+		return "", 0, err
 	}
-	finalMessage := string(serverMessage)
-	return finalMessage, nil
+
+	serverMessageReduced := make([]byte, n)
+	copy(serverMessageReduced, serverMessage)
+
+	finalMessage := string(serverMessageReduced)
+	serverMessage = nil
+
+	return finalMessage, n, nil
 }
 
 func scanLine() (line string, err error) {