Some refactorings for telegram package

telegram/init.go

@@ -0,0 +1,42 @@
+package telegram
+
+import (
+	"net"
+	"sync"
+	"time"
+)
+
+const telegramDialTimeout = 10 * time.Second
+
+var (
+	Direct Telegram
+	Middle Telegram
+
+	initOnce sync.Once
+)
+
+func Init() {
+	initOnce.Do(func() {
+		Direct = &directTelegram{
+			baseTelegram: baseTelegram{
+				dialer:      net.Dialer{Timeout: telegramDialTimeout},
+				v4DefaultDC: directV4DefaultIdx,
+				V6DefaultDC: directV6DefaultIdx,
+				v4Addresses: directV4Addresses,
+				v6Addresses: directV6Addresses,
+			},
+		}
+
+		tg := &middleTelegram{
+			baseTelegram: baseTelegram{
+				dialer: net.Dialer{Timeout: telegramDialTimeout},
+			},
+		}
+		if err := tg.update(); err != nil {
+			panic(err)
+		}
+		go tg.backgroundUpdate()
+
+		Middle = tg
+	})
+}