while (!isThreadBlockedOnInstanceOf(t, blocker)) {
      if (t.getState() == Thread.State.TERMINATED) {
        throw new RuntimeException("Thread " + t + " exited unexpectedly");
      }
      Thread.sleep(1);
    }
  }

  private static boolean isThreadBlockedOnInstanceOf(Thread t, Class<?> blocker) {
    return t.getState() == Thread.State.WAITING && blocker.isInstance(LockSupport.getBlocker(t));
  }

    while (!isThreadBlockedOnInstanceOf(t, blocker)) {
      if (t.getState() == Thread.State.TERMINATED) {
        throw new RuntimeException("Thread " + t + " exited unexpectedly");
      }
      Thread.sleep(1);
    }
  }

  private static boolean isThreadBlockedOnInstanceOf(Thread t, Class<?> blocker) {
    return t.getState() == Thread.State.WAITING && blocker.isInstance(LockSupport.getBlocker(t));
  }

        .build()
    assertThat(headers["Test-Instant"]).isEqualTo("Thu, 01 Jan 1970 00:00:00 GMT")
    assertThat(headers.getInstant("Test-Instant")).isEqualTo(expected)
  }

  @Test fun setDate() {
    val expected = Date(1000)
    val headers =
      Headers.Builder()
        .add("testDate", Date(0L))
        .set("testDate", expected)
        .build()

    assertEquals(THREAD_PRIORITY, thread.getPriority());
    assertEquals(THREAD_DAEMON, thread.isDaemon());
    assertSame(UNCAUGHT_EXCEPTION_HANDLER, thread.getUncaughtExceptionHandler());
    assertSame(Thread.State.NEW, thread.getState());

    assertFalse(completed);
    thread.start();
    thread.join();
    assertTrue(completed);
  }

  public void testNulls() {
    NullPointerTester npTester = new NullPointerTester();

    assertEquals(THREAD_PRIORITY, thread.getPriority());
    assertEquals(THREAD_DAEMON, thread.isDaemon());
    assertSame(UNCAUGHT_EXCEPTION_HANDLER, thread.getUncaughtExceptionHandler());
    assertSame(Thread.State.NEW, thread.getState());

    assertFalse(completed);
    thread.start();
    thread.join();
    assertTrue(completed);
  }

  public void testNulls() {
    NullPointerTester npTester = new NullPointerTester();