companies, or even industries — utilities useful for a sizable proportion of all Java
        programmers everywhere. If you can give enough detail such that any of us can imagine coming
        across a similar need in our own work, that's extremely helpful in studying how broadly
        useful the proposed change will be.

  - type: textarea
    attributes:
      label: Concrete Use Cases

# Using Dataclasses { #using-dataclasses }

FastAPI is built on top of **Pydantic**, and I have been showing you how to use Pydantic models to declare requests and responses.

But FastAPI also supports using <a href="https://docs.python.org/3/library/dataclasses.html" class="external-link" target="_blank">`dataclasses`</a> the same way:

{* ../../docs_src/dataclasses/tutorial001.py hl[1,7:12,19:20] *}

      limiter.acquire(); // #5
    }
    stopwatch.sleepMillis(4250); // #6, back to cold state (warmup period + repay last acquire)
    for (int i = 0; i < 11; i++) {
      limiter.acquire(); // #7, showing off the warmup starting from totally cold
    }

    // make sure the areas (times) remain the same, while permits are different
    assertEvents(
        "R0.00, R1.38, R1.13, R0.88, R0.63, R0.50, R0.50, R0.50", // #1

      limiter.acquire(); // #5
    }
    stopwatch.sleepMillis(4250); // #6, back to cold state (warmup period + repay last acquire)
    for (int i = 0; i < 11; i++) {
      limiter.acquire(); // #7, showing off the warmup starting from totally cold
    }

    // make sure the areas (times) remain the same, while permits are different
    assertEvents(
        "R0.00, R1.38, R1.13, R0.88, R0.63, R0.50, R0.50, R0.50", // #1

          protected void doStart() {
            // Never starts!
          }

          @Override
          protected void doCancelStart() {
            assertThat(state()).isEqualTo(Service.State.STOPPING);
            notifyStopped();
          }

          @Override
          protected void doStop() {
            throw new AssertionError(); // Should not be called.
          }
        };

        testDir = testFile.getParentFile(); // the testdata directory
      } catch (Exception ignore) {
        // probably URISyntaxException or IllegalArgumentException
        // fall back to copying URLs to files in the testDir == null block below
      }
    }

    if (testDir == null) {
      // testdata resources aren't file:// urls, so create a directory to store them in and then

    @Test
    @DisplayName("clone: copies fields and cached subject; instances are independent")
    void testCloneCopiesFieldsAndIndependence() throws Exception {
        // Use configuration-based constructor to also exercise copying of configuration/service fields
        JAASAuthenticator orig = new JAASAuthenticator(new HashMap<String, String>(), "DOM", "user", "pass");

      .addNetworkInterceptor(interceptor)
      .build()
    assertThat(original.interceptors.size).isEqualTo(0)
    assertThat(original.networkInterceptors.size).isEqualTo(0)
  }

  /**
   * When copying the client, stateful things like the connection pool are shared across all
   * clients.
   */
  @Test fun cloneSharesStatefulInstances() {
    val client = clientTestRule.newClient()

- **Asynchronous Operations**: Non-blocking suggestion requests with callback support
- **Index Management**: Automatic index creation, switching, and maintenance
- **Customizable Scoring**: User boost, document frequency, and query frequency weighting

## Technology Stack

- **Java**: 21+ (configured via parent POM)
- **OpenSearch**: Latest (provided scope)

 * string {@code "Foo<Bar>"}.
 *
 * <p>An {@code Escaper} instance is required to be stateless, and safe when used concurrently by
 * multiple threads.
 *
 * <p>Because, in general, escaping operates on the code points of a string and not on its
 * individual {@code char} values, it is not safe to assume that {@code escape(s)} is equivalent to