docs: public long writeGraphStructure(SameDiff sd) throws IOException {
          Preconditions.checkState(endStaticInfoOffset < 0, "Cannot write graph structure - already wrote end of static info marker");
          Pair<Integer, FlatBufferBuilder> h = encodeStaticHeader(UIInfoType.GRAPH_STRUCTURE);
  
          FlatBufferBuilder fbb2 = new FlatBufferBuilder(0);
          int graphStructureOffset = encodeGraphStructure(fbb2, sd);
          fbb2.finish(graphStructureOffset);
  
          return append(h.getSecond(), fbb2);
      }