import java.util.function.Supplier;
import java.util.stream.Collector;
import org.checkerframework.checker.nullness.qual.Nullable;

/** Collectors utilities for {@code common.collect.Table} internals. */
@GwtCompatible
@ElementTypesAreNonnullByDefault
@SuppressWarnings({"AndroidJdkLibsChecker", "Java7ApiChecker"})
@IgnoreJRERequirement // used only from APIs with Java 8 types in them

## Start otel-collector service

First, create an `otel-collector` backend with simple configuration.

```bash
kubectl apply -f ../otel.yaml -n observability
```

With following configuration, otel-collector will create a grpc receiver on port `4317`, and output to stdout. You can find more details from [here](https://github.com/open-telemetry/opentelemetry-collector).

```yaml
receivers:
  otlp:

        private PlannedNodeGraph computePlannedNodeGraph(QueryableExecutionPlan.ScheduledNodes scheduledWork) {
            PlannedNodeGraph.Collector collector = new PlannedNodeGraph.Collector(converterRegistry);
            scheduledWork.visitNodes((nodes, entryNodes) -> collector.collectNodes(nodes));
            return collector.getGraph();
        }

        private static class CalculateTaskGraphResult implements Result, CustomOperationTraceSerialization {

// [Ticker] would never be recovered by the garbage collector, and that
// if efficiency was a concern, code should use NewTicker instead and
// call [Ticker.Stop] when the ticker is no longer needed.
// As of Go 1.23, the garbage collector can recover unreferenced
// tickers, even if they haven't been stopped.
// The Stop method is no longer necessary to help the garbage collector.

    Value<Void> collectKeys(ValueConsumer consumer, ValueCollector<K> collector, ImmutableCollection.Builder<K> dest);

    void calculateExecutionTimeValue(Action<ExecutionTimeValue<? extends Map<? extends K, ? extends V>>> visitor);

    MapCollector<K, V> absentIgnoring();

    /**
     * Returns a collector that may never return a missing value.
     */

    // As it's basically a DAG traversal, we can keep a queue instead of making recursive calls.
    val allFiles = this
    val filesQueueToAnalyze = ArrayDeque(allFiles)
    val collector = InlineFunctionsCollector(allFiles.first().project, reifiedInlineFunctionsOnly = false) { declaration ->
        val containingFile = declaration.containingKtFile
        if (allFiles.add(containingFile)) {

     */
    @Override
    public TransformerContext initialize(ModelBuildingRequest request, ModelProblemCollector collector) {
        // We must assume the TransformerContext was created using this.newTransformerContextBuilder()
        DefaultModelProblemCollector problems = (DefaultModelProblemCollector) collector;
        return new TransformerContext() {

            @Override
            public Path locate(Path path) {

meshConfig:
  enableTracing: true
  extensionProviders:
  - name: test-otel
    opentelemetry:
      service: opentelemetry-collector.istio-system.svc.cluster.local
      port: 4317
  - name: test-otel-http
    opentelemetry:
      service: opentelemetry-collector.istio-system.svc.cluster.local
      port: 4318
      http:
        path: "v1/traces"
        timeout: 10s
        headers:

     */
    @Override
    public ModelTransformerContext initialize(ModelBuilderRequest request, ModelProblemCollector collector) {
        // We must assume the TransformerContext was created using this.newTransformerContextBuilder()
        DefaultModelProblemCollector problems = (DefaultModelProblemCollector) collector;
        return new ModelTransformerContext() {

            @Override
            public Path locate(Path path) {

  protobuf::TextFormat::Parser parser;
  // Don't produce errors when attempting to parse text format as it would fail
  // when the input is actually a binary file.
  NoOpErrorCollector collector;
  parser.RecordErrorsTo(&collector);
  // Attempt to parse as text.
  absl::string_view text_proto_without_prefix = text_proto;
  if (!prefix_to_strip.empty()) {
    TF_RETURN_IF_ERROR(