import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.collect.CollectPreconditions.checkNonnegative;
import static com.google.common.collect.CollectPreconditions.checkRemove;
import static java.util.Objects.requireNonNull;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;

    }
  }

  /**
   * Precondition tester for {@code Iterator.remove()} that throws an exception with a consistent
   * error message.
   */
  static void checkRemove(boolean canRemove) {
    checkState(canRemove, "no calls to next() since the last call to remove()");
  }

  private CollectPreconditions() {}

      entryIndex = backingMap.nextIndex(entryIndex);
      return result;
    }

    @Override
    public void remove() {
      checkForConcurrentModification();
      CollectPreconditions.checkRemove(toRemove != -1);
      size -= backingMap.removeEntry(toRemove);
      entryIndex = backingMap.nextIndexAfterRemove(entryIndex, toRemove);
      toRemove = -1;
      expectedModCount = backingMap.modCount;
    }