## Other Asynchronous Function Calls

As the testing function is now asynchronous, you can now also call (and `await`) other `async` functions apart from sending requests to your FastAPI application in your tests, exactly as you would call them anywhere else in your code.

!!! tip

   * exception.
   *
   * <p>When the underlying delegate throws an exception then this memoizing supplier will keep
   * delegating calls until it returns valid data.
   *
   * @param duration the length of time after a value is created that it should stop being returned
   *     by subsequent {@code get()} calls
   * @param unit the unit that {@code duration} is expressed in
   * @throws IllegalArgumentException if {@code duration} is not positive

        toRemove = mapEntry;
        return mapEntry.getKey();
      }

      @Override
      public void remove() {
        checkState(toRemove != null, "no calls to next() since the last call to remove()");
        size -= toRemove.getValue().getAndSet(0);
        backingEntries.remove();
        toRemove = null;
      }
    };
  }

  @Override

  public void testReturning() throws Exception {
    assertNull(Callables.returning(null).call());

    Object value = new Object();
    Callable<Object> callable = Callables.returning(value);
    assertSame(value, callable.call());
    // Expect the same value on subsequent calls
    assertSame(value, callable.call());
  }

  @J2ktIncompatible
  @GwtIncompatible
  public void testAsAsyncCallable() throws Exception {

   *
   * <p><b>Warning:</b> using a bounded executor may be counterproductive! If the thread pool fills
   * up, any time callers spend waiting for a thread may count toward their time limit, and in this
   * case the call may even time out before the target method is ever invoked.
   *
   * @param executor the ExecutorService that will execute the method calls on the target objects;

  }

  /**
   * Constructs an iterator across a sequence of the given size with the given initial position.
   * That is, the first call to {@link #nextIndex()} will return {@code position}, and the first
   * call to {@link #next()} will return the element at that index, if available. Calls to {@link
   * #previous()} can retrieve the preceding {@code position} elements.
   *

	
    // Register the handler on the manager
    instance.Register(manager, handler)
	
    // The typed instance is also used for calls
    conn := manager.Connection("host")
    resp, err := instance.Call(ctx, conn, grid.NewMSSWith(map[string]string{"myfield": "myvalue"}))
    if err == nil {
        fmt.Println("Got response with field", resp["result"])
    }
```

 *
 * When a single logical call requires multiple streams due to redirects or authorization
 * challenges, we prefer to use the same physical connection for all streams in the sequence. There
 * are potential performance and behavior consequences to this preference. To support this feature,
 * this class separates _allocations_ from _streams_. An allocation is created by a call, used for

    // Cancel some calls. That doesn't impact running or queued.
    a2.cancel()
    a3.cancel()
    assertThat(dispatcher.runningCalls())
      .containsExactlyInAnyOrder(a1, a2)
    assertThat(dispatcher.queuedCalls()).isEmpty()

    // Let the calls finish.
    waiting.countDown()
    t1.join()
    t2.join()

    // Now we should have 0 running calls and 0 queued calls.

      // racing addListener calls and addListener calls completing after the future completes.
      final Runnable listener =
          k % 2 == 0 ? collectResultsRunnable : collectResultsTimedGetRunnable;
      allTasks.add(Executors.callable(listener));
      allTasks.add(
          new Callable<@Nullable Void>() {
            @Override
            public @Nullable Void call() throws Exception {