If you want to stream data that can be structured as JSON, you should [Stream JSON Lines](../tutorial/stream-json-lines.md).

But if you want to **stream pure binary data** or strings, here's how you can do it.

/// info

Added in FastAPI 0.134.0.

///

## Use Cases { #use-cases }

You could use this if you want to stream pure strings, for example directly from the output of an **AI LLM** service.

    }

    /**
     * Returns a new immutable class-to-instance map containing the entries provided to this
     * builder.
     *
     * @throws IllegalArgumentException if duplicate keys were added
     */
    public ImmutableClassToInstanceMap<B> build() {
      ImmutableMap<Class<? extends B>, B> map = mapBuilder.buildOrThrow();
      if (map.isEmpty()) {
        return of();
      } else {

    //    [a1, a2, a3, b1, b2], [a1, b2, a2, a3, b2], [a1, b2, b3, a2, a3], etc.)
    // 2. It's possible for subscribers to actually be dispatched to in a different order than they
    //    were added to the queue. It's easily possible for one thread to take the head of the
    //    queue, immediately followed by another thread taking the next element in the queue. That

            threads[i].start();
        }

        // Wait for all threads to complete
        for (Thread thread : threads) {
            thread.join();
        }

        // Verify all entries were added
        assertEquals(1000, entry.getChildren().size());
    }

   *     changed, this is <i>definitely</i> the first time {@code object} has been added to the
   *     filter. If the bits haven't changed, this <i>might</i> be the first time {@code object} has
   *     been added to the filter. Note that {@code put(t)} always returns the <i>opposite</i>
   *     result to what {@code mightContain(t)} would have returned at the time it is called.

            assertTrue(result.contains("            <plugin>"), "Plugin element should be properly indented");
        }

        @Test
        @DisplayName("should format pluginManagement with proper indentation when added")
        void shouldFormatPluginManagementWithProperIndentationWhenAdded() throws Exception {
            // Use a POM that will trigger pluginManagement addition by having a plugin without version
            String pomXml = """

 * (yet). Instead, we maintain a list of projects that are excluded from
 * formatting, until we reach a point where we can comfortably format them
 * in one go without too much disruption.
 *
 * Any new sub-projects must not be added to the exclusions list!
 *
 * To perform a reformat, run:
 *
 *     ./gradlew spotlessApply
 *
 * To check the current format, run:
 *
 *     ./gradlew spotlessJavaCheck
 *

The order of each tag metadata dictionary also defines the order shown in the docs UI.

For example, even though `users` would go after `items` in alphabetical order, it is shown before them, because we added their metadata as the first dictionary in the list.

## OpenAPI URL { #openapi-url }

By default, the OpenAPI schema is served at `/openapi.json`.

But you can configure it with the parameter `openapi_url`.

   * service listeners}. This is extracted into its own object so that {@link ServiceListener} could
   * be made {@code static} and its instances can be safely constructed and added in the {@link
   * ServiceManager} constructor without having to close over the partially constructed {@link
   * ServiceManager} instance (i.e. avoid leaking a pointer to {@code this}).
   */

        .build()
    val certB =
      HeldCertificate
        .Builder()
        .serialNumber(3L)
        .signedBy(certA)
        .build()
    val cleaner = get(root.certificate)
    // Root is added!
    assertThat(cleaner.clean(list(certB, certA), "hostname")).isEqualTo(
      list(certB, certA, root),
    )
  }

  @Test
  fun unorderedChainOfCertificatesWithRoot() {
    val root =