checkStrength(map, Strength.WEAK, Strength.STRONG);
    assertThat(map.entryFactory).isEqualTo(EntryFactory.WEAK);
  }

  public void testSetWeakValues() {
    LocalCache<Object, Object> map = makeLocalCache(createCacheBuilder().weakValues());
    checkStrength(map, Strength.STRONG, Strength.WEAK);
    assertThat(map.entryFactory).isEqualTo(EntryFactory.STRONG);
  }

    checkStrength(map, Strength.WEAK, Strength.STRONG);
    assertThat(map.entryFactory).isEqualTo(EntryFactory.WEAK);
  }

  public void testSetWeakValues() {
    LocalCache<Object, Object> map = makeLocalCache(createCacheBuilder().weakValues());
    checkStrength(map, Strength.STRONG, Strength.WEAK);
    assertThat(map.entryFactory).isEqualTo(EntryFactory.STRONG);
  }

        map.put(key, localCache.getOrLoad(key));
      }
      return ImmutableMap.copyOf(map);
    }
  }

  /**
   * Any updates to LocalCache.Strength used in CacheBuilder need to be matched in this class for
   * compilation purposes.
   */
  enum Strength {
    /*
     * TODO(kevinb): If we strongly reference the value and aren't loading, we needn't wrap the
     * value. This could save ~8 bytes per entry.
     */

import static org.junit.Assert.assertThrows;

import com.google.common.base.Function;
import com.google.common.collect.Interners.InternerImpl;
import com.google.common.collect.MapMakerInternalMap.Strength;
import com.google.common.testing.GcFinalization;
import com.google.common.testing.NullPointerTester;
import java.lang.ref.WeakReference;
import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;

    assertThat(spec.maximumSize).isEqualTo(20);
    assertThat(spec.maximumWeight).isNull();
    assertThat(spec.concurrencyLevel).isEqualTo(30);
    assertThat(spec.keyStrength).isEqualTo(Strength.WEAK);
    assertThat(spec.valueStrength).isEqualTo(Strength.WEAK);
    assertThat(spec.writeExpirationTimeUnit).isEqualTo(HOURS);
    assertThat(spec.accessExpirationTimeUnit).isEqualTo(MINUTES);
    assertThat(spec.writeExpirationDuration).isEqualTo(1L);

import static org.junit.Assert.assertThrows;

import com.google.common.base.Function;
import com.google.common.collect.Interners.InternerImpl;
import com.google.common.collect.MapMakerInternalMap.Strength;
import com.google.common.testing.GcFinalization;
import com.google.common.testing.NullPointerTester;
import java.lang.ref.WeakReference;
import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;

  }

  private CacheBuilderFactory cacheFactory() {
    return new CacheBuilderFactory()
        .withKeyStrengths(ImmutableSet.of(Strength.STRONG, Strength.WEAK))
        .withValueStrengths(ImmutableSet.copyOf(Strength.values()))
        .withConcurrencyLevels(ImmutableSet.of(1, 4, 16, 64))
        .withMaximumSizes(ImmutableSet.of(0, 1, 10, 100, 1000))

 * limitations under the License.
 */

package com.google.common.collect;

import static com.google.common.collect.MapMakerInternalMap.Strength.STRONG;
import static com.google.common.collect.MapMakerInternalMap.Strength.WEAK;
import static com.google.common.testing.SerializableTester.reserialize;
import static com.google.common.testing.SerializableTester.reserializeAndAssert;

    // would cause one to be evicted.
    return new CacheBuilderFactory()
        .withKeyStrengths(ImmutableSet.of(Strength.STRONG, Strength.WEAK))
        .withValueStrengths(ImmutableSet.copyOf(Strength.values()))
        .withConcurrencyLevels(ImmutableSet.of(1, 4, 16, 64))
        .withMaximumSizes(ImmutableSet.of(400, 1000))

That's why it makes a lot of sense to use asynchronous ⏸🔀⏯ code for web APIs.

This kind of asynchronicity is what made NodeJS popular (even though NodeJS is not parallel) and that's the strength of Go as a programming language.

And that's the same level of performance you get with **FastAPI**.