import com.google.common.util.concurrent.internal.InternalFutureFailureAccess;
import com.google.common.util.concurrent.internal.InternalFutures;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.errorprone.annotations.concurrent.LazyInit;
import java.util.Collection;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.CancellationException;