httpx.post(callback_url, json={"description": "Invoice paid", "paid": True})
```

But possibly the most important part of the callback is making sure that your API user (the external developer) implements the *external API* correctly, according to the data that *your API* is going to send in the request body of the callback, etc.

     * This class manages the temporary file creation, writing operations,
     * and atomic updates to ensure data consistency during modifications.
     */
    protected class MappingUpdater implements Closeable {

        /** Flag indicating whether changes should be committed to the file. */
        protected boolean isCommit = false;

        /** Temporary file used for writing updates before committing. */

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Resolves a version for a plugin.
 *
 * @since 3.0
 */
@Named
@Singleton
public class DefaultPluginVersionResolver implements PluginVersionResolver {
    private static final String REPOSITORY_CONTEXT = org.apache.maven.api.services.RequestTrace.CONTEXT_PLUGIN;

    private static final Object CACHE_KEY = new Object();

        return "KuromojiFile [path=" + path + ", kuromojiItemList=" + kuromojiItemList + ", id=" + id + "]";
    }

    /**
     * An updater for Kuromoji files.
     */
    protected class KuromojiUpdater implements Closeable {

        /** True if the changes have been committed. */
        protected boolean isCommit = false;

        /** The new file. */
        protected File newFile;

import java.lang.reflect.Array;
import java.util.NoSuchElementException;

/**
 * Linked list for Seasar2.
 *
 * @author higa
 * @param <E> the element type
 */
public class SLinkedList<E> implements Cloneable, Externalizable {

    static final long serialVersionUID = 1L;

    private transient Entry header = new Entry(null, null, null);

    private transient int size = 0;

    /**

 * {@link InternalSession#getAllServices()}.
 */
@Named
@Typed({ProjectManager.class, Service.class})
@SessionScoped
public class DefaultProjectManager implements ProjectManager {

    private final InternalMavenSession session;
    private final ArtifactManager artifactManager;

    @Inject

    assertThat(e)
        .hasMessageThat()
        .isEqualTo("Timed out waiting for Foo [STARTING] to reach the RUNNING state.");
  }

  private class FakeService extends AbstractExecutionThreadService implements TearDown {

    private final ExecutorService executor = newSingleThreadExecutor();

    FakeService() {
      tearDownStack.addTearDown(this);
    }

    volatile int startupCalled = 0;

  /**
   * Intercepts calls to a {@code Map} to check that {@code setUpRan} is true when they happen. Then
   * forwards the calls to the underlying {@code Map}.
   */
  private static class CheckSetUpInvocationHandler implements InvocationHandler, Serializable {
    private final Map<String, String> map;
    private final AtomicBoolean setUpRan;

    CheckSetUpInvocationHandler(Map<String, String> map, AtomicBoolean setUpRan) {

 * more efficient implementation.
 *
 * @author James Sexton
 * @param <N> Node parameter type
 * @param <E> Edge parameter type
 * @since 20.0
 */
@Beta
public abstract class AbstractNetwork<N, E> implements Network<N, E> {
  /** Constructor for use by subclasses. */
  public AbstractNetwork() {}

  @Override
  public Graph<N> asGraph() {
    return new AbstractGraph<N>() {
      @Override

 * more efficient implementation.
 *
 * @author James Sexton
 * @param <N> Node parameter type
 */
abstract class AbstractBaseGraph<N> implements BaseGraph<N> {

  /**
   * Returns the number of edges in this graph; used to calculate the size of {@link Graph#edges()}.
   * This implementation requires O(|N|) time. Classes extending this one may manually keep track of