docs: private WritableMemory growCombinedMemBuffer(final int itemSpaceNeeded) {
      final long memBytes = mem_.getCapacity();
      final int needBytes = (itemSpaceNeeded << 3) + COMBINED_BUFFER; //+ preamble + min & max
      assert needBytes > memBytes;
  
      memReqSvr = (memReqSvr == null) ? mem_.getMemoryRequestServer() : memReqSvr;
  
      final WritableMemory newMem = memReqSvr.request(needBytes);
  
      mem_.copyTo(0, newMem, 0, memBytes);
  
      memReqSvr.requestClose(mem_, newMem);
  
      return newMem;
    }