import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.errorprone.annotations.DoNotCall;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.util.AbstractMap;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Map;
import java.util.NavigableMap;
import java.util.SortedMap;
import java.util.TreeMap;
import java.util.function.BinaryOperator;

    @SuppressWarnings("unchecked")
    static <T extends Throwable> void uncheckedThrow(Throwable t) throws T {
        throw (T) t; // rely on vacuous cast
    }

    static class LazyMap<K, V> extends AbstractMap<K, V> {
        private final Supplier<Map<K, V>> supplier;
        private volatile Map<K, V> delegate;

        LazyMap(Supplier<Map<K, V>> supplier) {
            this.supplier = supplier;
        }