I'll show you some concrete examples in the next chapters.

---

Then the next concepts to consider are all about the program running your actual API (e.g. Uvicorn).

## Program and Process

     */
    void add(Problem.Severity severity, String message, int line, int column, Exception cause);

    /**
     * The next messages will be bound to this source. When calling this method again, previous messages keep
     * their source, but the next messages will use the new source.
     *
     * @param source a source
     */
    void setSource(String source);

    /**
     *

## Integrated middlewares

**FastAPI** includes several middlewares for common use cases, we'll see next how to use them.

/// note | "Technical Details"

For the next examples, you could also use `from starlette.middleware.something import SomethingMiddleware`.

      StringBuilder sb = new StringBuilder();
      Iterator<String> iterator = components.iterator();
      if (iterator.hasNext()) {
        sb.append(iterator.next().toString());
        while (iterator.hasNext()) {
          sb.append(DELIMITER_STRING);
          sb.append(iterator.next());
        }
      }
      dummy ^= sb.toString().length();
    }
    return dummy;
  }

  /**

        @Override
        public boolean hasNext() {
          return backingEntries.hasNext();
        }

        @Override
        public Multiset.Entry<E> next() {
          final Map.Entry<E, Integer> mapEntry = backingEntries.next();
          return new Multisets.AbstractEntry<E>() {
            @Override
            public E getElement() {
              return mapEntry.getKey();
            }

				b.RunParallel(func(pb *testing.PB) {
					rng := rand.New(rand.NewSource(time.Now().UnixNano()))
					n := 0
					var latency int64
					managers := grid.Managers
					hosts := grid.Hosts
					for pb.Next() {
						// Pick a random manager.
						src, dst := rng.Intn(len(managers)), rng.Intn(len(managers))
						if src == dst {
							dst = (dst + 1) % len(managers)
						}
						local := managers[src]

		tr := NewReader(&buf)
		h, err := tr.Next()
		if err != ErrInsecurePath {
			t.Errorf("tr.Next for file %q: got err %v, want ErrInsecurePath", path, err)
			continue
		}
		if h.Name != path {
			t.Errorf("tr.Next for file %q: got name %q, want %q", path, h.Name, path)
		}
		// Error should not be sticky.
		h, err = tr.Next()
		if err != nil {

    }.test();
  }

  public void testIteratorNoSuchElementException() {
    Iterator<E> iterator = collection.iterator();
    while (iterator.hasNext()) {
      iterator.next();
    }

    assertThrows(NoSuchElementException.class, () -> iterator.next());
  }

    private final ReferenceEntry<K, V> next;

    public DummyEntry(K key, int hash, ReferenceEntry<K, V> next) {
      this.key = key;
      this.hash = hash;
      this.next = next;
    }

    public static <K, V> DummyEntry<K, V> create(
        K key, int hash, @Nullable ReferenceEntry<K, V> next) {
      return new DummyEntry<>(key, hash, next);
    }

    public void clearKey() {

    private final ReferenceEntry<K, V> next;

    public DummyEntry(K key, int hash, ReferenceEntry<K, V> next) {
      this.key = key;
      this.hash = hash;
      this.next = next;
    }

    public static <K, V> DummyEntry<K, V> create(
        K key, int hash, @Nullable ReferenceEntry<K, V> next) {
      return new DummyEntry<>(key, hash, next);
    }

    public void clearKey() {