httpdns 缓存策略，特殊接口获取 httpdns 服务

foudations/httpdns-base/src/main/java/com/mogo/httpdns/MogoHttpDnsHandler.java

@@ -0,0 +1,29 @@
+package com.mogo.httpdns;
+
+import androidx.annotation.Keep;
+
+import com.alibaba.android.arouter.launcher.ARouter;
+
+public
+/**
+ * @author congtaowang
+ * @since 2020/11/19
+ *
+ * 描述
+ */
+@Keep
+class MogoHttpDnsHandler {
+
+    private static IMogoHttpDns sHttpDns;
+
+    public static IMogoHttpDns getHttpDnsApi() {
+        if ( sHttpDns == null ) {
+            synchronized ( MogoHttpDnsHandler.class ) {
+                if ( sHttpDns == null ) {
+                    sHttpDns = ARouter.getInstance().navigation( IMogoHttpDns.class );
+                }
+            }
+        }
+        return sHttpDns;
+    }
+}