```Python
with open("./somefile.txt") as f:
    contents = f.read()
    print(contents)
```

Por baixo dos panos, o código `open("./somefile.txt")` cria um objeto que é chamado de "Gerenciador de Contexto".

Quando o bloco `with` finaliza, ele se certifica de fechar o arquivo, mesmo que tenha ocorrido alguma exceção.

Ele tem:

* Performance seriamente impressionante.
* Suporte a WebSocket.
* Suporte a GraphQL.
* Tarefas de processamento interno por trás dos panos.
* Eventos de inicialização e encerramento.
* Cliente de testes construído com HTTPX.
* Respostas CORS, GZip, Arquivos Estáticos, Streaming.
* Suporte para Sessão e Cookie.
* 100% coberto por testes.

    Iterable<String> list = Lists.newArrayList("cool", "pants");
    Iterator<String> iterator = list.iterator();
    assertEquals("pants", find(iterator, equalTo("pants")));
    assertFalse(iterator.hasNext());
  }

  public void testFind_notPresent() {
    Iterable<String> list = Lists.newArrayList("cool", "pants");
    Iterator<String> iterator = list.iterator();

    long nanos = unit.toNanos(timeout);
    synchronized (lock) {
      while (true) {
        if (shutdown && runningTasks == 0) {
          return true;
        } else if (nanos <= 0) {
          return false;
        } else {
          long now = System.nanoTime();
          NANOSECONDS.timedWait(lock, nanos);
          nanos -= System.nanoTime() - now; // subtract the actual time we waited

internal inline fun Lockable.notify() = (this as Object).notify()

internal inline fun Lockable.notifyAll() = (this as Object).notifyAll()

internal inline fun Lockable.awaitNanos(nanos: Long) {
  val ms = nanos / 1_000_000L
  val ns = nanos - (ms * 1_000_000L)
  if (ms > 0L || nanos > 0) {
    (this as Object).wait(ms, ns.toInt())
  }
}

internal inline fun Lockable.assertLockNotHeld() {
  if (assertionsEnabled && Thread.holdsLock(this)) {

      long nanos = expirationNanos;
      long now = System.nanoTime();
      if (nanos == 0 || now - nanos >= 0) {
        synchronized (lock) {
          if (nanos == expirationNanos) { // recheck for lost race
            T t = delegate.get();
            value = t;
            nanos = now + durationNanos;
            // In the very unlikely event that nanos is 0, set it to 1;

    Iterable<String> list = Lists.newArrayList("cool", "pants");
    Iterator<String> iterator = list.iterator();
    assertEquals("pants", find(iterator, equalTo("pants")));
    assertFalse(iterator.hasNext());
  }

  public void testFind_notPresent() {
    Iterable<String> list = Lists.newArrayList("cool", "pants");
    Iterator<String> iterator = list.iterator();

    long nanos = unit.toNanos(timeout);
    synchronized (lock) {
      while (true) {
        if (shutdown && runningTasks == 0) {
          return true;
        } else if (nanos <= 0) {
          return false;
        } else {
          long now = System.nanoTime();
          NANOSECONDS.timedWait(lock, nanos);
          nanos -= System.nanoTime() - now; // subtract the actual time we waited

 *
 * <p>This class is thread-safe.
 *
 * @author Jige Yu
 * @since 10.0
 */
@NullMarked
@GwtCompatible
public class FakeTicker extends Ticker {

  private final AtomicLong nanos = new AtomicLong();
  private volatile long autoIncrementStepNanos;

  /** Advances the ticker value by {@code time} in {@code timeUnit}. */
  @SuppressWarnings("GoodTime") // should accept a java.time.Duration

      long nanos = expirationNanos;
      long now = System.nanoTime();
      if (nanos == 0 || now - nanos >= 0) {
        synchronized (lock) {
          if (nanos == expirationNanos) { // recheck for lost race
            T t = delegate.get();
            value = t;
            nanos = now + durationNanos;
            // In the very unlikely event that nanos is 0, set it to 1;