Network Expansion

<dubbo:protocol networker="xxx" />
<!-- The default value setting, when <dubbo:protocol> does not configure the networker attribute, use this configuration -->
<dubbo:provider networker="xxx" />

src
 |-main
    |-java
        |-com
            |-xxx
                |-XxxNetworker.java (implement Networker interface)
    |-resources
        |-META-INF
            |-dubbo
                |-org.apache.dubbo.remoting.p2p.Networker (plain text file, content: xxx=com.xxx.XxxNetworker)

package com.xxx;
 
import org.apache.dubbo.remoting.p2p.Networker;
 
public class XxxNetworker implements Networker {
    public Group lookup(URL url) {
        //...
    }
}

xxx=com.xxx.XxxNetworker