library/src/main/java/com/qiniu/android/dns/DnsManager.java
public DnsManager putHosts(String domain, String ip, int provider) {
        hosts.put(domain, new Hosts.Value(ip, provider));
        return this;
    }
public DnsManager putHosts(String domain, String ip, int provider) {
        hosts.put(domain, new Hosts.Value(ip, provider));
        return this;
    }
插入指定运营商的hosts配置

@param domain   域名
@param ip       ip
@param provider 运营商，见 NetworkInfo
@return 当前的DnsManager，便于链式调用