// Writer implements buffering for an [io.Writer] object.
// If an error occurs writing to a [Writer], no more data will be
// accepted and all subsequent writes, and [Writer.Flush], will return the error.
// After all data has been written, the client should call the
// [Writer.Flush] method to guarantee all data has been forwarded to
// the underlying [io.Writer].
type Writer struct {
	err error
	buf []byte
	n   int
	wr  io.Writer

{* ../../docs_src/settings/app03_an_py39/main.py hl[1,11] *}

Then for any subsequent call of `get_settings()` in the dependencies for the next requests, instead of executing the internal code of `get_settings()` and creating a new `Settings` object, it will return the same object that was returned on the first call, again and again.

#### `lru_cache` Technical Details { #lru-cache-technical-details }

  @CollectionSize.Require(absent = ZERO)
  public void testSubList_originalListSetAffectsSubList() {
    List<E> subList = getList().subList(0, 1);
    getList().set(0, e3());
    assertEquals(
        "A set() call to a list after a sublist has been created "
            + "should be reflected in the sublist",
        singletonList(e3()),
        subList);
  }

  @ListFeature.Require(SUPPORTS_REMOVE_WITH_INDEX)

    public void remove() {
      checkForConcurrentModification();
      checkState(current != null, "no calls to next() since the last call to remove()");
      if (current != next) { // after call to next()
        previous = current.previous;
        nextIndex--;
      } else { // after call to previous()
        next = current.next;
      }
      removeNode(current);
      current = null;
      expectedModCount = modCount;

    val pooled2 = planReusePooledConnection(connect, connect.routes)
    if (pooled2 != null) return pooled2

    return connect
  }

  /**
   * Returns the connection already attached to the call if it's eligible for a new exchange.
   *
   * If the call's connection exists and is eligible for another exchange, it is returned. If it
   * exists but cannot be used for another exchange, it is closed and this returns null.

internal val Response.exchangeAccessor: Exchange?
  get() = this.exchange

internal val Exchange.connectionAccessor: RealConnection
  get() = this.connection

    }
    assertEquals(
        "multiset.size() should be the sum of the counts of all entries",
        size,
        getMultiset().size());
  }

  /** Call the {@code setCount()} method under test, and check its return value. */
  abstract void setCountCheckReturnValue(E element, int count);

  /**
   * Call the {@code setCount()} method under test, but do not check its return value. Callers

 * Tests for {@link RequestParam} covering enum mechanics and edge cases.
 */
@ExtendWith(MockitoExtension.class)
public class RequestParamTest {

    // Happy path: values() returns all constants in declaration order
    @Test
    @DisplayName("values() returns all declared constants in order")
    void valuesContainsAllInOrder() {
        RequestParam[] values = RequestParam.values();

        assertNotNull(values, "values() must not return null");

# OpenAPI Webhooks { #openapi-webhooks }

There are cases where you want to tell your API **users** that your app could call *their* app (sending a request) with some data, normally to **notify** of some type of **event**.

This means that instead of the normal process of your users sending requests to your API, it's **your API** (or your app) that could **send requests to their system** (to their API, their app).

This is normally called a **webhook**.

   * skipped element by immediately calling {@code remove()} on the returned fluent iterable's
   * iterator, as the {@code Iterator} contract states that a call to {@code * remove()} before a
   * call to {@code next()} will throw an {@link IllegalStateException}.
   *
   * <p><b>{@code Stream} equivalent:</b> {@link Stream#skip} (same).
   */
  public final FluentIterable<E> skip(int numberToSkip) {