message: Fix compilation issue after rebasing
diff: @@ -287,19 +287,19 @@ public final class Graph implements ExecutionEnvironment, AutoCloseable {
  try (Reference ref = subgraph.ref()) {
  for (int i = 0; i < ninputs; i++) {
  - Operation op = new Operation(subgraph, inputHandles[i]);
  - inputs[i] = new Output<>(op, inputIndices[i]);
  + Operation op = new GraphNode(subgraph, inputHandles[i]);
  + inputs[i] = op.output(inputIndices[i]);
  }
  for (int i = 0; i < noutputs; i++) {
  - Operation op = new Operation(subgraph, outputHandles[i]);
  - outputs[i] = new Output<>(op, outputIndices[i]);
  + Operation op = new GraphNode(subgraph, outputHandles[i]);
  + outputs[i] = op.output(outputIndices[i]);
  }
  subgraphBuilder.buildSubgraph(subgraph, inputs, outputs);
  for (int i = 0, j = noutputs; i < noutputs; i++, j++) {
  - outputHandlesAndIndices[i] = outputs[i].op().getUnsafeNativeHandle();
  + outputHandlesAndIndices[i] = outputs[i].getUnsafeNativeHandle();
  outputHandlesAndIndices[j] = (long) outputs[i].index();
  }
  }
  @@ -330,7 +330,7 @@ public final class Graph implements ExecutionEnvironment, AutoCloseable {
  try (Reference ref = ref()) {
  for (int i = 0; i < ninputs; i++) {
  - inputHandles[i] = inputs[i].op().getUnsafeNativeHandle();
  + inputHandles[i] = inputs[i].getUnsafeNativeHandle();
  inputIndices[i] = inputs[i].index();
  }
  @@ -338,8 +338,8 @@ public final class Graph implements ExecutionEnvironment, AutoCloseable {
  whileLoop(nativeHandle, inputHandles, inputIndices, name, cgBuilder, bgBuilder);
  for (int i = 0, j = ninputs; i < ninputs; ++i, ++j) {
  - Operation op = new Operation(this, outputHandlesAndIndices[i]);
  - outputs[i] = new Output<>(op, (int) outputHandlesAndIndices[j]);
  + Operation op = new GraphNode(this, outputHandlesAndIndices[i]);
  + outputs[i] = op.output((int) outputHandlesAndIndices[j]);
  }
  }
  return outputs;
  