public int getHeartbeatInterval() {
        return getInt(HEARTBEAT_INTERVAL_KEY, DEFAULT_HEARTBEAT_INTERVAL);
    }
the properties of polaris registry

@author <a href=mailto:bner666@gmail.com>ZhangLibin</a>
registry/registry-polaris/src/main/java/com/alipay/sofa/rpc/registry/polaris/PolarisRegistryProperties.java