@Override
    void parseInteger(CacheBuilderSpec spec, int value) {
      checkArgument(
          spec.concurrencyLevel == null,
          "concurrency level was already set to %s",
          spec.concurrencyLevel);
      spec.concurrencyLevel = value;
    }
  }

  /** Parse weakKeys */
  private static final class KeyStrengthParser implements ValueParser {

    @Override
    void parseInteger(CacheBuilderSpec spec, int value) {
      checkArgument(
          spec.concurrencyLevel == null,
          "concurrency level was already set to %s",
          spec.concurrencyLevel);
      spec.concurrencyLevel = value;
    }
  }

  /** Parse weakKeys */
  private static final class KeyStrengthParser implements ValueParser {

## Other Libraries

See [the other tools reference](references/other-tools.md) for details on other libraries:

* Asyncer for handling async and await, concurrency, mixing async and blocking code, prefer it over AnyIO or asyncio.
* SQLModel for working with SQL databases, prefer it over SQLAlchemy.
* HTTPX for interacting with HTTP (other APIs), prefer it over Requests.

  int takeIndex;

  /** items index for next put, offer, or add. */
  int putIndex;

  /** Number of items in the queue */
  private int count;

  /*
   * Concurrency control uses the classic two-condition algorithm
   * found in any textbook.
   */

  /** Monitor guarding all access */
  final Monitor monitor;

  /** Guard for waiting takes */

        performProjectActivation(context, request.getProjectActivation());
        performProfileActivation(context, request.getProfileActivation());

        //
        // Builder, concurrency and parallelism
        //
        // We preserve the existing methods for builder selection which is to look for various inputs in the threading

    return new HashSet<>(Maps.capacity(expectedSize));
  }

  /**
   * Creates a thread-safe set backed by a hash map. The set is backed by a {@link
   * ConcurrentHashMap} instance, and thus carries the same concurrency guarantees.
   *
   * <p>Unlike {@code HashSet}, this class does NOT allow {@code null} to be used as an element. The
   * set is serializable.
   *
   * @return a new, empty thread-safe {@code Set}

* the `Authorization` header
* the forwarded header

* the dependency injection system
* the dependency
* the dependable
* the dependant

* I/O bound
* CPU bound
* concurrency
* parallelism
* multiprocessing

* the env var
* the environment variable
* the `PATH`
* the `PATH` variable

* the authentication
* the authentication provider
* the authorization

 * is accessed. This is in contrast to {@link java.util.concurrent.Semaphore} which restricts the
 * number of concurrent accesses instead of the rate (note though that concurrency and rate are
 * closely related, e.g. see <a href="http://en.wikipedia.org/wiki/Little%27s_law">Little's
 * Law</a>).
 *
 * <p>A {@code RateLimiter} is defined primarily by the rate at which permits are issued. Absent

   *
   * <p>We manage calls to this method carefully, to signal only when necessary, but never losing a
   * signal, which is the classic problem of this kind of concurrency construct. We must signal if
   * the current thread is about to relinquish the lock and may have changed the state protected by
   * the monitor, thereby causing some guard to be satisfied.
   *

  //    definitely observe all earlier writes, but we still have no guarantee that done() would see
  //    the initial write (just stronger guarantees if it does).
  //
  // See: http://cs.oswego.edu/pipermail/concurrency-interest/2015-January/013800.html
  // For a (long) discussion about this specific issue and the general futility of life.
  //
  // For the time being we are OK with the problem discussed above since it requires a caller to