inFinished: Boolean,
  ) {
    pushQueue.execute("$connectionName[$streamId] onHeaders") {
      val cancel = pushObserver.onHeaders(streamId, requestHeaders, inFinished)
      ignoreIoExceptions {
        if (cancel) writer.rstStream(streamId, ErrorCode.CANCEL)
        if (cancel || inFinished) {
          withLock {
            currentPushRequests.remove(streamId)
          }
        }
      }

          // Note: The only way this CAS could fail is if cancel() has raced with us. That is ok.
          boolean unused = casValue(this, valueToSet, failure);
        }
        return true;
      }
      localValue = value(); // we lost the cas, fall through and maybe cancel
    }
    // The future has already been set to something. If it is cancellation we should cancel the
    // incoming future.

 * Prefer to alternate IP addresses from different address families, (IPv6 / IPv4), starting with IPv6.
 * Don't start a new attempt until 250 ms after the most recent attempt was started.
 * Keep whichever TCP connection succeeds first and cancel all the others.

    inputFuture.cancel(true); // argument is ignored
    assertThrows(CancellationException.class, () -> resultFuture.get());
  }

  public void testFutureGetThrowsCancellationIfOutputCancelled() throws Exception {
    inputFuture.set(SLOW_OUTPUT_VALID_INPUT_DATA);
    outputFuture.cancel(true); // argument is ignored

    inputFuture.cancel(true); // argument is ignored
    assertThrows(CancellationException.class, () -> resultFuture.get());
  }

  public void testFutureGetThrowsCancellationIfOutputCancelled() throws Exception {
    inputFuture.set(SLOW_OUTPUT_VALID_INPUT_DATA);
    outputFuture.cancel(true); // argument is ignored

    assertFailed(future, cause);
  }

  public void testCanceled() throws Exception {
    assertThat(future.cancel(false /* mayInterruptIfRunning */)).isTrue();
    assertCancelled(future, false);
  }

  public void testInterrupted() throws Exception {
    assertThat(future.cancel(true /* mayInterruptIfRunning */)).isTrue();
    assertCancelled(future, true);
  }

    async.setFuture(inner);
    async.cancel(false);
    assertTrue(inner.isCancelled());
    assertFalse(inner.wasInterrupted());
    assertThrows(CancellationException.class, inner::get);
  }

  public void testCancel_beforeSet() throws Exception {
    SettableFuture<Object> async = SettableFuture.create();
    async.cancel(true);
    assertFalse(async.set(42));
  }

   * exception.
   *
   * @throws IllegalStateException when the call has already been executed.
   */
  fun enqueue(responseCallback: Callback)

  /** Cancels the request, if possible. Requests that are already complete cannot be canceled. */
  fun cancel()

  /**
   * Returns true if this call has been either [executed][execute] or [enqueued][enqueue]. It is an
   * error to execute a call more than once.
   */

	}
	return testCases
}()

const (
	EnvTestEtcdBackend = "_MINIO_ETCD_TEST_SERVER"
)

func (s *TestSuiteIAM) setUpEtcd(c *check, etcdServer string) {
	ctx, cancel := context.WithTimeout(context.Background(), testDefaultTimeout)
	defer cancel()

	configCmds := []string{
		"etcd",
		"endpoints=" + etcdServer,
		"path_prefix=" + mustGetUUID(),
	}
	_, err := s.adm.SetConfigKV(ctx, strings.Join(configCmds, " "))

            }
          });
      executor.execute(
          () -> {
            future.cancel(true);
            if (!future.isDone()) {
              errorMessage.set("Cancel call exited before future was complete.");
            }
          });
      try {
        future.get();
      } catch (Throwable t) {