}

  /**
   * Streams lines from a URL, stopping when our callback returns false, or we have read all of the
   * lines.
   *
   * @param url the URL to read from
   * @param charset the charset used to decode the input stream; see {@link StandardCharsets} for
   *     helpful predefined constants
   * @param callback the LineProcessor to use to handle the lines
   * @return the output of processing the lines

/**
 * A thread that reads from an input stream line by line and maintains a buffer of recent lines.
 * This class provides functionality to read input stream data asynchronously,
 * optionally process each line with a callback function, and maintain a circular buffer
 * of recent lines for retrieval.
 */
public class InputStreamThread extends Thread {
    /** Logger instance for this class */

import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Proxy;
import java.util.List;
import java.util.concurrent.atomic.AtomicLong;
import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.Connection;
import okhttp3.EventListener;
import okhttp3.Handshake;
import okhttp3.HttpUrl;
import okhttp3.OkHttpClient;
import okhttp3.Protocol;
import okhttp3.Request;
import okhttp3.Response;

        defaultResponseHeaders.forEach(header -> callback.accept(header.getFirst(), header.getSecond()));
        final List<Pair<String, String>> headers = responseHeaderMap.get(mimeType);
        if (headers != null) {
            headers.forEach(header -> callback.accept(header.getFirst(), header.getSecond()));
        }
    }

    val latch = CountDownLatch(1)
    val exceptionRef = AtomicReference<Throwable>()
    val call = client.newCall(request)
    call.timeout().timeout(250, TimeUnit.MILLISECONDS)
    call.enqueue(
      object : Callback {
        override fun onFailure(
          call: Call,
          e: IOException,
        ) {
          exceptionRef.set(e)
          latch.countDown()
        }

        @Throws(IOException::class)

                if (builderEntityCall != null) {
                    builderEntityCall.callback(builder);
                }
                bulkBuilder.add((IndexRequestBuilder) builder);
            } else if (builder instanceof UpdateRequestBuilder) {
                if (builderEntityCall != null) {
                    builderEntityCall.callback(builder);
                }
                bulkBuilder.add((UpdateRequestBuilder) builder);

この（外部開発者の）視点を一時的に採用すると、その *外部 API* に対してパラメータ、ボディ用の Pydantic モデル、レスポンスなどをどこに置くのが自然かがより明確に感じられるでしょう。

///

### コールバック用 APIRouter を作成 { #create-a-callback-apirouter }

まず、1 つ以上のコールバックを含む新しい `APIRouter` を作成します。

{* ../../docs_src/openapi_callbacks/tutorial001_py310.py hl[1,23] *}

### コールバックの path operation を作成 { #create-the-callback-path-operation }

上で作成したのと同じ `APIRouter` を使って、コールバックの *path operation* を作成します。

見た目は通常の FastAPI の *path operation* と同じです:

                        },
                        "callbacks": {
                            "post_callback": {
                                "/post-callback": {
                                    "post": {
                                        "summary": "Post Callback",
                                        "operationId": "baz_post_callback",
                                        "requestBody": {

 * and performant but introduces some testing difficulties. This test exercises the two fallback
 * strategies.
 *
 * <ul>
 *   <li>SafeAtomicHelper: uses Atomic FieldsUpdaters to implement synchronization
 *   <li>SynchronizedHelper: uses {@code synchronized} blocks for synchronization
 * </ul>
 *
 * To force selection of our fallback strategies we load {@link AggregateFutureState} (and all of

          responseCallback.onResponse(this@RealCall, response)
        } catch (e: IOException) {
          if (signalledCallback) {
            // Do not signal the callback twice!
            Platform.get().log("Callback failure for ${toLoggableString()}", Platform.INFO, e)
          } else {
            responseCallback.onFailure(this@RealCall, e)
          }
        } catch (t: Throwable) {
          cancel()