assertTrue(limiter.tryAcquire(0, SECONDS));
    assertFalse(limiter.tryAcquire(0, SECONDS));
    assertFalse(limiter.tryAcquire(0, SECONDS));
    stopwatch.sleepMillis(100);
    assertFalse(limiter.tryAcquire(0, SECONDS));
  }

  public void testTryAcquire_someWaitAllowed() {
    RateLimiter limiter = RateLimiter.create(5.0, stopwatch);
    assertTrue(limiter.tryAcquire(0, SECONDS));

    assertTrue(limiter.tryAcquire(0, SECONDS));
    assertFalse(limiter.tryAcquire(0, SECONDS));
    assertFalse(limiter.tryAcquire(0, SECONDS));
    stopwatch.sleepMillis(100);
    assertFalse(limiter.tryAcquire(0, SECONDS));
  }

  public void testTryAcquire_someWaitAllowed() {
    RateLimiter limiter = RateLimiter.create(5.0, stopwatch);
    assertTrue(limiter.tryAcquire(0, SECONDS));

    }
    if (HOURS.convert(nanos, NANOSECONDS) > 0) {
      return HOURS;
    }
    if (MINUTES.convert(nanos, NANOSECONDS) > 0) {
      return MINUTES;
    }
    if (SECONDS.convert(nanos, NANOSECONDS) > 0) {
      return SECONDS;
    }
    if (MILLISECONDS.convert(nanos, NANOSECONDS) > 0) {
      return MILLISECONDS;
    }
    if (MICROSECONDS.convert(nanos, NANOSECONDS) > 0) {
      return MICROSECONDS;

    future.set(1);
    assertEquals(1, future.get(-1, SECONDS).intValue());
  }

  @J2ktIncompatible
  @GwtIncompatible // threads
  public void testOverflowTimeout() throws Exception {
    // First, sanity check that naive multiplication would really overflow to a negative number:
    long nanosPerSecond = NANOSECONDS.convert(1, SECONDS);
    assertThat(nanosPerSecond * Long.MAX_VALUE).isLessThan(0L);

    future.set(1);
    assertEquals(1, future.get(-1, SECONDS).intValue());
  }

  @J2ktIncompatible
  @GwtIncompatible // threads
  public void testOverflowTimeout() throws Exception {
    // First, sanity check that naive multiplication would really overflow to a negative number:
    long nanosPerSecond = NANOSECONDS.convert(1, SECONDS);
    assertThat(nanosPerSecond * Long.MAX_VALUE).isLessThan(0L);

import static com.google.common.testing.ReflectionFreeAssertThrows.assertThrows;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.NANOSECONDS;
import static java.util.concurrent.TimeUnit.SECONDS;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import java.time.Duration;
import java.util.concurrent.Callable;
import java.util.concurrent.CountDownLatch;

    }

    protected LoadingCache<String, List<Pattern>> createFilterCache(final String type) {
        return CacheBuilder.newBuilder()//
                .expireAfterWrite(filterCacheExpireAfterWrite, TimeUnit.SECONDS)//
                .build(new CacheLoader<String, List<Pattern>>() {

                    @Override
                    public List<Pattern> load(final String key) {

    FluentIterable<TimeUnit> unused = FluentIterable.from(TimeUnit.values()).append(SECONDS);
  }

  public void testFromArrayAndIteratorRemove() {
    FluentIterable<TimeUnit> units = FluentIterable.from(TimeUnit.values());
    assertThrows(UnsupportedOperationException.class, () -> removeIf(units, equalTo(SECONDS)));
  }

  public void testFrom() {
    assertEquals(
        ImmutableList.of(1, 2, 3, 4),

This includes, for example:

* Email notifications sent after performing an action:
    * As connecting to an email server and sending an email tends to be "slow" (several seconds), you can return the response right away and send the email notification in the background.
* Processing data:

 */

package com.google.common.hash;

import static com.google.common.truth.Truth.assertThat;
import static java.nio.charset.StandardCharsets.UTF_8;
import static java.util.concurrent.TimeUnit.SECONDS;
import static org.junit.Assert.assertThrows;

import com.google.common.base.Stopwatch;
import com.google.common.collect.ImmutableSet;
import com.google.common.hash.BloomFilterStrategies.LockFreeBitArray;