How to use the opennms.Client.getMetadata function in opennms

getClientWithMetadata() {
        if (!this.clientWithMetadata) {
              const self = this;
              const http = self.client.http;
              const client = Client.getMetadata(http.server, http, self.timeout)
                .then(function(metadata) {
                    // Ensure the OpenNMS we are talking to is compatible
                    if (metadata.apiVersion() < 2) {
                        throw new Error("Unsupported Version");
                    }
                    const server = API.OnmsServer.newBuilder(http.server.url)
                        .setName(http.server.name)
                        .setAuth(http.server.auth)
                        .setMetadata(metadata)
                        .build();
                    http.server = server;
                    return self.client;
                }).catch(function(e) {
                    // in case of error, reset the client, otherwise
                    // the datasource may never recover
                    self.clientWithMetadata = void 0;