Fetch DC ips from Telegram

mtglib/internal/telegram/dc_addresses.go

@@ -0,0 +1,19 @@
+package telegram
+
+type dcAddresses struct {
+	v4 map[int][]tgAddr
+	v6 map[int][]tgAddr
+}
+
+func (a dcAddresses) getV4(dc int) []tgAddr {
+	return a.v4[dc]
+}
+
+func (a dcAddresses) getV6(dc int) []tgAddr {
+	return a.v6[dc]
+}
+
+func (a dcAddresses) isValidDC(dc int) bool {
+	_, ok := a.v4[dc]
+	return ok
+}