///

### 非 async 的*路径操作函数* { #non-async-path-operation-functions }

你也可以使用常规的 `def` 函数（没有 `async`），并以同样的方式使用 `yield`。

FastAPI 会确保其正确运行，从而不阻塞事件循环。

由于此时函数不是 async，正确的返回类型应为 `Iterable[Item]`：

{* ../../docs_src/server_sent_events/tutorial001_py310.py ln[28:31] hl[29] *}

### 无返回类型 { #no-return-type }

你也可以省略返回类型。FastAPI 将使用 [`jsonable_encoder`](./encoder.md) 转换数据并发送。

   */
  @CanIgnoreReturnValue
  public B withFeatures(Feature<?>... features) {
    return withFeatures(asList(features));
  }

  @CanIgnoreReturnValue
  public B withFeatures(Iterable<? extends Feature<?>> features) {
    for (Feature<?> feature : features) {
      this.features.add(feature);
    }
    return self();
  }

  public Set<Feature<?>> getFeatures() {

      return mapGenerator.samples();
    }

    @Override
    public Entry<K, V>[] createArray(int length) {
      return mapGenerator.createArray(length);
    }

    @Override
    public Iterable<Entry<K, V>> order(List<Entry<K, V>> insertionOrder) {
      return mapGenerator.order(insertionOrder);
    }

    @Override
    public Map<K, V> create(Object... elements) {

    longManyValuesAccumulatorByAddAllVarargs = new StatsAccumulator();
    longManyValuesAccumulatorByAddAllVarargs.addAll(Longs.toArray(LONG_MANY_VALUES));
  }

  private static StatsAccumulator statsAccumulatorOf(Iterable<? extends Number> values) {
    StatsAccumulator accumulator = new StatsAccumulator();
    accumulator.addAll(values);
    return accumulator;
  }

  public void testCount() {

    return fromArrayWithExpectedSize(array, expectedSize);
  }

  /**
   * Returns an immutable set containing each of {@code elements}, minus duplicates, in the order
   * each appears first in the source iterable. This method iterates over {@code elements} only
   * once.
   *
   * <p><b>Performance note:</b> This method will sometimes recognize that the actual copy operation

          @Override
          public Object load(Object key) throws Exception {
            return new Object();
          }

          @Override
          public Map<Object, Object> loadAll(Iterable<?> keys) throws Exception {
            Map<Object, Object> result = new HashMap<>();
            for (Object key : keys) {
              Object value = new Object();
              result.put(key, value);

      checkEmpty(cache);
    }
  }

  /* ---------------- Local utilities -------------- */

  /** Most of the tests in this class run against every one of these caches. */
  private Iterable<LoadingCache<Object, Object>> caches() {
    // lots of different ways to configure a LoadingCache
    CacheBuilderFactory factory = cacheFactory();
    return Iterables.transform(

   * }
   *
   * <p>In particular, this is a no-op if {@code values} is empty.
   *
   * @return {@code true} if the multimap changed
   */
  @CanIgnoreReturnValue
  boolean putAll(@ParametricNullness K key, Iterable<? extends V> values);

  /**
   * Stores all key-value pairs of {@code multimap} in this multimap, in the order returned by
   * {@code multimap.entries()}.
   *
   * @return {@code true} if the multimap changed

          @Override
          public Object load(Object key) throws Exception {
            return new Object();
          }

          @Override
          public Map<Object, Object> loadAll(Iterable<?> keys) throws Exception {
            Map<Object, Object> result = new HashMap<>();
            for (Object key : keys) {
              Object value = new Object();
              result.put(key, value);

    assertTrue(emptyConcat.isEmpty());
  }

  public void testConcat_infiniteIterable() throws IOException {
    CharSource source = CharSource.wrap("abcd");
    Iterable<CharSource> cycle = Iterables.cycle(ImmutableList.of(source));
    CharSource concatenated = CharSource.concat(cycle);

    String expected = "abcdabcd";