*
   * Lock lockA = factory1.newReentrantLock(MyLockOrder.FIRST);
   * Lock lockB = factory1.newReentrantLock(MyLockOrder.FIRST);
   * Lock lockC = factory2.newReentrantLock(MyLockOrder.FIRST);
   *
   * lockA.lock();
   *
   * lockB.lock();  // will throw an IllegalStateException
   * lockC.lock();  // will throw an IllegalStateException
   *
   * lockA.lock();  // reentrant acquisition is okay
   * }

     * always under a lock.
     */
    private static final class SupplantableFuture implements Cancellable {
      private final ReentrantLock lock;

      @GuardedBy("lock")
      private Future<@Nullable Void> currentFuture;

      SupplantableFuture(ReentrantLock lock, Future<@Nullable Void> currentFuture) {
        this.lock = lock;
        this.currentFuture = currentFuture;
      }

    }

    BlockDoc getBlock(String name) {
        def block = classBlocks.find { it.name == name }
        if (block) {
            return block
        }
        for (extensionDoc in classExtensions) {
            block = extensionDoc.extensionBlocks.find { it.name == name }
            if (block) {
                return block
            }
        }

      while (true) {
        var tryAgain = false
        var readBytesDelivered = -1L
        var errorExceptionToDeliver: IOException? = null

        // 1. Decide what to do in a synchronized block.

        withLock {
          val doReadTimeout = doReadTimeout()
          if (doReadTimeout) {
            readTimeout.enter()
          }
          try {

        <span class="sponsor-badge">sponsor</span>
        <img class="sponsor-image" src="/img/sponsors/blockbee-banner.png" />
      </a>
    </div>
    <div class="item">

   *
   * Lock lockA = factory1.newReentrantLock(MyLockOrder.FIRST);
   * Lock lockB = factory1.newReentrantLock(MyLockOrder.FIRST);
   * Lock lockC = factory2.newReentrantLock(MyLockOrder.FIRST);
   *
   * lockA.lock();
   *
   * lockB.lock();  // will throw an IllegalStateException
   * lockC.lock();  // will throw an IllegalStateException
   *
   * lockA.lock();  // reentrant acquisition is okay
   * }

    void testClockTimezone() {
        MonotonicClock clock = MonotonicClock.get();

        assertEquals(ZoneOffset.UTC, clock.getZone(), "Clock should use UTC timezone");

        // Verify that attempting to change timezone returns the same instance
        Clock newClock = clock.withZone(ZoneId.systemDefault());
        assertSame(clock, newClock, "withZone() should return the same clock instance");
    }

    @Test

	dm1st := NewDRWMutex(ds, "aap")
	dm2nd := NewDRWMutex(ds, "aap")

	dm1st.Lock(id, source)

	// Release lock after 10 seconds
	go func() {
		time.Sleep(5 * testDrwMutexAcquireTimeout)
		// fmt.Println("Unlocking dm1")

		dm1st.Unlock(t.Context())
	}()

	dm2nd.Lock(id, source)

	// fmt.Printf("2nd lock obtained after 1st lock is released\n")
	time.Sleep(testDrwMutexRefreshCallTimeout * 2)

import (
	"crypto/rsa"
	"crypto/x509"
	"encoding/base64"
	"encoding/pem"
	"log"
)

func bytesToPrivateKey(priv []byte) (*rsa.PrivateKey, error) {
	// Try PEM
	if block, _ := pem.Decode(priv); block != nil {
		return x509.ParsePKCS1PrivateKey(block.Bytes)
	}
	// Try base 64
	dst := make([]byte, base64.StdEncoding.DecodedLen(len(priv)))
	if n, err := base64.StdEncoding.Decode(dst, priv); err == nil {

   */
  @GuardedBy("lock")
  private int runningTasks = 0;

  @GuardedBy("lock")
  private boolean shutdown = false;

  @Override
  public void execute(Runnable command) {
    startTask();
    try {
      command.run();
    } finally {
      endTask();
    }
  }

  @Override
  public boolean isShutdown() {
    synchronized (lock) {
      return shutdown;
    }
  }