for (int j = 0; j < NUM_THREADS; j++) {
        @SuppressWarnings("unused") // https://errorprone.info/bugpattern/FutureReturnValueIgnored
        Future<?> possiblyIgnoredError = executorService.submit(addTask);
      }
      @SuppressWarnings("unused") // https://errorprone.info/bugpattern/FutureReturnValueIgnored
      Future<?> possiblyIgnoredError = executorService.submit(executeTask);

      @SuppressWarnings("unused") // https://errorprone.info/bugpattern/FutureReturnValueIgnored
      Future<?> possiblyIgnoredError = threadPool.submit(new Producer(q, 20));
      @SuppressWarnings("unused") // https://errorprone.info/bugpattern/FutureReturnValueIgnored
      Future<?> possiblyIgnoredError1 = threadPool.submit(new Producer(q, 20));
      @SuppressWarnings("unused") // https://errorprone.info/bugpattern/FutureReturnValueIgnored

@com.google.errorprone.annotations.CheckReturnValue

import com.google.common.util.concurrent.ExecutionError;
import com.google.common.util.concurrent.UncheckedExecutionException;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.errorprone.annotations.CompatibleWith;
import com.google.errorprone.annotations.DoNotMock;
import java.util.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.ConcurrentMap;

 * the License.
 */

package com.google.common.reflect;

import com.google.common.collect.ForwardingMap;
import com.google.common.collect.ImmutableMap;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.errorprone.annotations.DoNotCall;
import java.util.Map;
import javax.annotation.CheckForNull;

/**
 * A type-to-instance map backed by an {@link ImmutableMap}. See also {@link

 * limitations under the License.
 */

/**
 * Testing utilities. This package is a part of the open-source <a
 * href="https://github.com/google/guava">Guava</a> library.
 */
@com.google.errorprone.annotations.CheckReturnValue
@javax.annotation.ParametersAreNonnullByDefault

 *
 * <p>This package is a part of the open-source <a href="https://github.com/google/guava">Guava</a>
 * library.
 */
@CheckReturnValue
package com.google.common.escape.testing;

 * <p>This package is a part of the open-source <a href="https://github.com/google/guava">Guava</a>
 * library.
 */
@CheckReturnValue
@ParametersAreNonnullByDefault
package com.google.common.graph;

import com.google.errorprone.annotations.CheckReturnValue;

 * library.
 *
 * @author Craig Berry
 */
@CheckReturnValue
@ParametersAreNonnullByDefault
package com.google.common.net;

import com.google.errorprone.annotations.CheckReturnValue;

    @SuppressWarnings("unused") // https://errorprone.info/bugpattern/FutureReturnValueIgnored
    Future<?> possiblyIgnoredError = testExecutor.schedule(DO_NOTHING, 10, TimeUnit.MINUTES);
    mock.assertLastMethodCalled("scheduleRunnable", 10, TimeUnit.MINUTES);

    @SuppressWarnings("unused") // https://errorprone.info/bugpattern/FutureReturnValueIgnored
    Future<?> possiblyIgnoredError1 =