src/main/java/com/alipay/remoting/rpc/RpcClient.java
public void enableConnHeartbeat(String addr) {
        Url url = this.addressParser.parse(addr);
        this.enableConnHeartbeat(url);
    }
public void enableConnHeartbeat(String addr) {
        Url url = this.addressParser.parse(addr);
        this.enableConnHeartbeat(url);
    }
Enable heart beat for a certain connection.
If this address not connected, then do nothing.
<p>
Notice: this method takes no effect on a stand alone connection.

@param addr