private static Set<ServerName> transformServerNames(GetMastersResponse resp) {
    return resp.getMasterServersList().stream()
      .map(s -> ProtobufUtil.toServerName(s.getServerName())).collect(Collectors.toSet());
  }
Builds the default master address end point if it is not specified in the configuration.
<p/>
Will be called in {@code HBaseTestingUtility}.
hbase-client/src/main/java/org/apache/hadoop/hbase/client/MasterRegistry.java