@Override
  public CompletableFuture<List<RegionInfo>> getRegions(ServerName serverName) {
    return this.<List<RegionInfo>> newAdminCaller()
      .action((controller, stub) -> this.<GetOnlineRegionRequest, GetOnlineRegionResponse,
        List<RegionInfo>> adminCall(controller, stub,
          RequestConverter.buildGetOnlineRegionRequest(),
          (s, c, req, done) -> s.getOnlineRegion(c, req, done),
          resp -> ProtobufUtil.getRegionInfos(resp)))
      .serverName(serverName).call();
  }
Utility for completing passed TableState {@link CompletableFuture} <code>future</code> using
passed parameters. Sets error or boolean result ('true' if table matches the passed-in
targetState).
hbase-client/src/main/java/org/apache/hadoop/hbase/client/RawAsyncHBaseAdmin.java