Endpoint toEndpoint() {
        return rpcTrafficSourceBuilder.toEndpoint();
    }
EndpointDependencyBuilder is a wrapper of {@link RPCTrafficSourceBuilder}, and only exposes to build endpoint
relation relative sources.

@since 9.0.0
oap-server/analyzer/agent-analyzer/src/main/java/org/apache/skywalking/oap/server/analyzer/provider/trace/parser/listener/EndpointDependencyBuilder.java