*/
  final long reserve(int permits) {
    checkPermits(permits);
    synchronized (mutex()) {
      return reserveAndGetWaitLength(permits, stopwatch.readMicros());
    }
  }

  /**
   * Acquires a permit from this {@code RateLimiter} if it can be obtained without exceeding the
   * specified {@code timeout}, or returns {@code false} immediately (without waiting) if the permit

  }

  /**
   * Acquires permits from this {@link RateLimiter} if it can be acquired immediately without delay.
   *
   * <p>This method is equivalent to {@code tryAcquire(permits, 0, anyUnit)}.
   *
   * @param permits the number of permits to acquire
   * @return {@code true} if the permits were acquired, {@code false} otherwise
   * @throws IllegalArgumentException if the requested number of permits is negative or zero
   * @since 14.0

    assertTrue("Unable to acquire initial permit", r.tryAcquire());
    assertFalse("Capable of acquiring secondary permit", r.tryAcquire());
  }

  public void testDoubleMinValueCanAcquireExactlyOnce() {
    RateLimiter r = RateLimiter.create(Double.MIN_VALUE, stopwatch);
    assertTrue("Unable to acquire initial permit", r.tryAcquire());
    assertFalse("Capable of acquiring an additional permit", r.tryAcquire());

    assertTrue("Unable to acquire initial permit", r.tryAcquire());
    assertFalse("Capable of acquiring secondary permit", r.tryAcquire());
  }

  public void testDoubleMinValueCanAcquireExactlyOnce() {
    RateLimiter r = RateLimiter.create(Double.MIN_VALUE, stopwatch);
    assertTrue("Unable to acquire initial permit", r.tryAcquire());
    assertFalse("Capable of acquiring an additional permit", r.tryAcquire());

   * "permits / time", thus "1 / rate = time / permits". Thus, "1/rate" (time / permits) times
   * "permits" gives time, i.e., integrals on this function (which is what storedPermitsToWaitTime()
   * computes) correspond to minimum intervals between subsequent requests, for the specified number
   * of requested permits.
   *

 *  New: OkHttp includes a user-agent by default, like `okhttp/2.1.0-RC1`.
 *  Fix: Handle response code `308 Permanent Redirect`.
 *  Fix: Don't skip the callback if a call is canceled.
 *  Fix: Permit hostnames with underscores.
 *  Fix: Permit overriding the content-type in `OkApacheClient`.
 *  Fix: Use the socket factory for direct connections.
 *  Fix: Honor `OkUrlFactory` APIs that disable redirects.

   *     result in more than {@link Integer#MAX_VALUE} occurrences of the element
   * @throws NullPointerException if {@code element} is null and this implementation does not permit
   *     null elements. Note that if {@code occurrences} is zero, the implementation may opt to
   *     return normally.
   */
  @CanIgnoreReturnValue
  int add(@ParametricNullness E element, int occurrences);

   *     result in more than {@link Integer#MAX_VALUE} occurrences of the element
   * @throws NullPointerException if {@code element} is null and this implementation does not permit
   *     null elements. Note that if {@code occurrences} is zero, the implementation may opt to
   *     return normally.
   */
  @CanIgnoreReturnValue
  int add(@ParametricNullness E element, int occurrences);

 * typically false on Windows.
 *
 * If this returns false we won't permit simultaneous reads and writes. When writes commit we need
 * to delete the previous snapshots, and that won't succeed if the file is open. (We do permit
 * multiple simultaneous reads.)
 *
 * @param file a file in the directory to check. This file shouldn't already exist!
 */

 * unbounded, attempted additions may fail due to resource exhaustion (causing {@code
 * OutOfMemoryError}). This class does not permit {@code null} elements. A priority queue relying on
 * {@linkplain Comparable natural ordering} also does not permit insertion of non-comparable objects
 * (doing so results in {@code ClassCastException}).
 *