message: fix: add default block
diff: @@ -21,7 +21,7 @@ export class RootChain extends BaseToken<IPOSClientConfig> {
  getLastChildBlock() {
  return this.method("getLastChildBlock").then(method => {
  - return method.read<string>({}, this.client.config.rootChainDefaultBlock);
  + return method.read<string>({}, this.client.config.rootChainDefaultBlock||'finalized');
  });
  }
  