RegionSpaceUseReportRequest buildRegionSpaceUseReportRequest(RegionSizeStore regionSizes) {
    RegionSpaceUseReportRequest.Builder request = RegionSpaceUseReportRequest.newBuilder();
    for (Entry<RegionInfo, RegionSize> entry : regionSizes) {
      request.addSpaceUse(convertRegionSize(entry.getKey(), entry.getValue().getSize()));
    }
    return request.build();
  }
Builds a {@link RegionSpaceUseReportRequest} protobuf message from the region size map.
@param regionSizes The size in bytes of regions
@return The corresponding protocol buffer message.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java