library/src/main/java/com/qiniu/android/dns/DnsManager.java
public void onNetworkChange(NetworkInfo info) {
        clearCache();
        this.info = info == null ? NetworkInfo.normal : info;
        synchronized (resolvers) {
            index = 0;
        }
    }
public void onNetworkChange(NetworkInfo info) {
        clearCache();
        this.info = info == null ? NetworkInfo.normal : info;
        synchronized (resolvers) {
            index = 0;
        }
    }
当网络发生变化时，通知当前的网络信息

@param info 网络信息