* by multiple concurrent threads.
 *
 * @param <K> the type of the cache's keys, which are not permitted to be null
 * @param <V> the type of the cache's values, which are not permitted to be null
 * @author Charles Fry
 * @since 10.0
 */
@DoNotMock("Use CacheBuilder.newBuilder().build()")
@GwtCompatible
public interface Cache<K, V> {

  /**

   * FeatureSpecificTestSuiteBuilder.suppressing()}.
   */
  /*
   * TODO(cpovirk): or we could make HOLES_FORBIDDEN a feature. Or we could declare that
   * implementations are permitted to throw IAE if a hole is requested, and we could update
   * test*Hole to permit IAE. (But might this ignore genuine bugs?) But see the TODO above
   * testLower, which could make this all unnecessary
   */

   * analysis that that means "plain {@code T}" rather than the inferred type {@code @Nullable T}.
   * (And even if annotations on local variables were permitted as an optional hint, no annotation
   * would be the right tool for the job here: {@code @Nullable} is the annotation that we're trying
   * to get rid of, and {@code @NonNull} would be wrong for our use case for the same reason as

    assertEquals(s, xmlEscaper.escape(s));

    // Test ASCII control characters.
    for (char ch = 0; ch < 0x20; ch++) {
      if (ch == '\t' || ch == '\n' || ch == '\r') {
        // Only these whitespace chars are permitted in XML,
        if (shouldEscapeWhitespaceChars) {
          assertEscaping(xmlEscaper, "&#x" + Integer.toHexString(ch).toUpperCase() + ";", ch);
        } else {
          assertUnescaped(xmlEscaper, ch);
        }

   * with {@code FeatureSpecificTestSuiteBuilder.suppressing()} until <a
   * href="https://bugs.openjdk.org/browse/JDK-6409434">JDK-6409434</a> is fixed. It's unclear
   * whether nulls were to be permitted or forbidden, but presumably the eventual fix will be to
   * permit them, as it seems more likely that code would depend on that behavior than on the other.
   * Thus, we say the bug is in set(), which fails to support null.

   * analysis that that means "plain {@code T}" rather than the inferred type {@code @Nullable T}.
   * (And even if annotations on local variables were permitted as an optional hint, no annotation
   * would be the right tool for the job here: {@code @Nullable} is the annotation that we're trying
   * to get rid of, and {@code @NonNull} would be wrong for our use case for the same reason as

import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.EnumMap;
import java.util.Map;

/**
 * A {@code BiMap} backed by two {@code EnumMap} instances. Null keys and values are not permitted.
 * An {@code EnumBiMap} and its inverse are both serializable.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#bimap">{@code BiMap}</a>.
 *

import java.util.Map;
import org.jspecify.annotations.Nullable;

/**
 * A {@code BiMap} backed by an {@code EnumMap} instance for keys-to-values, and a {@code HashMap}
 * instance for values-to-keys. Null keys are not permitted, but null values are. An {@code
 * EnumHashBiMap} and its inverse are both serializable.
 *
 * <p>See the Guava User Guide article on <a href=

   *
   * <ul>
   *   <li>Any part containing non-ASCII characters is considered valid.
   *   <li>Underscores ('_') are permitted wherever dashes ('-') are permitted.
   *   <li>Parts other than the final part may start with a digit, as mandated by <a
   *       href="https://tools.ietf.org/html/rfc1123#section-2">RFC 1123</a>.
   * </ul>
   *

      } else {
        "scheduled after ${formatDuration(executeNanoTime - now)}"
      }
    }

    // Insert in chronological order. Always compare deltas because nanoTime() is permitted to wrap.
    var insertAt = futureTasks.indexOfFirst { it.nextExecuteNanoTime - now > delayNanos }
    if (insertAt == -1) insertAt = futureTasks.size
    futureTasks.add(insertAt, task)