docs: public void dropGraph(long graphId) {
          val builder = new FlatBufferBuilder(128);
  
          val off = FlatDropRequest.createFlatDropRequest(builder, graphId);
          builder.finish(off);
  
          val req = FlatDropRequest.getRootAsFlatDropRequest(builder.dataBuffer());
  
          val v = blockingStub.forgetGraph(req);
          if (v.status() != 0)
              throw new ND4JIllegalStateException("registerGraph() gRPC call failed");
      }