</div>

### Model for Input and Output in Docs { #model-for-input-and-output-in-docs }

And if you check all the available Schemas (JSON Schemas) in OpenAPI, you will see that there are two, one `Item-Input` and one `Item-Output`.

For `Item-Input`, `description` is **not required**, it doesn't have a red asterisk.

But for `Item-Output`, `description` is **required**, it has a red asterisk.

<div class="screenshot">

 * domains which are both public suffixes and addressable as hosts; {@code "uk.com"} is one example.
 * Using the subset of public suffixes that are {@linkplain #isRegistrySuffix() registry suffixes},
 * one can get a better result, as only a few registry suffixes are addressable. However, the most

 * @author mbechler
 *
 * <p>This interface is intended for internal use.</p>
 */
public interface BufferCache {

    /**
     * Gets a buffer from the cache or creates a new one if the cache is empty.
     *
     * @return a buffer from the cache, or a new one
     */
    byte[] getBuffer();

    /**
     * Return a buffer to the cache
     *
     * @param buf the buffer to return to the cache for reuse
     */

### One Load Balancer - Multiple Worker Containers { #one-load-balancer-multiple-worker-containers }

It is used by many companies including Mozilla, Red Hat and Eventbrite.

It was one of the first examples of **automatic API documentation**, and this was specifically one of the first ideas that inspired "the search for" **FastAPI**.

/// note

     * <p>
     * Note: only one, this method or {@link #getRecommendedVersion()} method must return non-{@code null} value.
     */
    @Nullable
    VersionRange getVersionRange();

    /**
     * Returns the recommended version of this constraint, or {@code null} if none.
     * <p>
     * Note: only one, this method or {@link #getVersionRange()} method must return non-{@code null} value.

       * errorMessageTemplate parameters: It is unlikely that callers intend for their string
       * template to be null (though we do handle that case gracefully at runtime). I've left this
       * one as it is because one of our users has defined a wrapper API around Preconditions,
       * declaring a checkState method that accepts a possibly null template. So we'd need to update
       * that user first.
       */

You would have **one single `engine` object** for all your code to connect to the same database.

{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[14:18] hl[14:15,17:18] *}

Using `check_same_thread=False` allows FastAPI to use the same SQLite database in different threads. This is necessary as **one single request** could use **more than one thread** (for example in dependencies).

 * `::1` will reach the IPv6 server.
 *
 * By orchestrating two different servers with the same port but different IP addresses, we can
 * test what OkHttp does when both are reachable, or if only one is reachable.
 *
 * This test only runs on host machines that have both IPv4 and IPv6 addresses for localhost.
 */
@Timeout(30)
class FastFallbackTest {
  @RegisterExtension
  val clientTestRule = OkHttpClientTestRule()

  public void testEmptyMultisetPollLast() {
    assertNull(sortedMultiset.pollLastEntry());
  }

  @CollectionSize.Require(ONE)
  public void testSingletonMultisetFirst() {
    assertEquals(a, sortedMultiset.firstEntry());
  }

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(ONE)
  public void testSingletonMultisetPollFirst() {
    assertEquals(a, sortedMultiset.pollFirstEntry());