* - 2 requests happen concurrently to a host that can be coalesced onto a single connection.
   * - Both request discover no existing connection. They both make a connection.
   * - The first request "wins the race".
   * - The second request discovers it "lost the race" and closes the connection it just opened.
   * - The second request uses the coalesced connection from request1.

        routes = routes,
        requireMultiplexed = planToReplace != null && planToReplace.isReady,
      ) ?: return null

    // If we coalesced our connection, remember the replaced connection's route. That way if the
    // coalesced connection later fails we don't waste a valid route.
    if (planToReplace != null) {
      nextRouteToTry = planToReplace.route
      planToReplace.closeQuietly()
    }

    assertEquals(!rangeSet.asDescendingSetOfRanges().iterator().hasNext(), rangeSet.isEmpty());

    List<Range<C>> asRanges = ImmutableList.copyOf(rangeSet.asRanges());

    // test that connected ranges are coalesced
    for (int i = 0; i + 1 < asRanges.size(); i++) {
      Range<C> range1 = asRanges.get(i);
      Range<C> range2 = asRanges.get(i + 1);
      assertFalse(range1.isConnected(range2));
    }

    coalescedRange = coalesce(coalescedRange, value, lowerEntry);

    Entry<Cut<K>, RangeMapEntry<K, V>> higherEntry =
        entriesByLowerBound.floorEntry(range.upperBound);
    coalescedRange = coalesce(coalescedRange, value, higherEntry);

    return coalescedRange;
  }

  /** Returns the range that spans the given range and entry, if the entry can be coalesced. */

   * connect to the given range and value.
   *
   * <p>Even if the input range is empty, if it is connected on both sides by ranges mapped to the
   * same value those two ranges will be coalesced.
   *
   * <p><b>Note:</b> coalescing requires calling {@code .equals()} on any connected values, which
   * may be expensive depending on the value type. Using this method on range maps with large values

    coalescedRange = coalesce(coalescedRange, value, lowerEntry);

    Entry<Cut<K>, RangeMapEntry<K, V>> higherEntry =
        entriesByLowerBound.floorEntry(range.upperBound);
    coalescedRange = coalesce(coalescedRange, value, higherEntry);

    return coalescedRange;
  }

  /** Returns the range that spans the given range and entry, if the entry can be coalesced. */

   * range set for which both {@code a.enclosesAll(b)} and {@code a.encloses(range)}.
   *
   * <p>Note that {@code range} will be {@linkplain Range#span(Range) coalesced} with any ranges in
   * the range set that are {@linkplain Range#isConnected(Range) connected} with it. Moreover, if
   * {@code range} is empty, this is a no-op.
   *

   * range set for which both {@code a.enclosesAll(b)} and {@code a.encloses(range)}.
   *
   * <p>Note that {@code range} will be {@linkplain Range#span(Range) coalesced} with any ranges in
   * the range set that are {@linkplain Range#isConnected(Range) connected} with it. Moreover, if
   * {@code range} is empty, this is a no-op.
   *

   *  * A authorization challenge (HTTP 401 and 407) that is satisfied by the [Authenticator].
   *  * A retryable server failure (HTTP 503 with a `Retry-After: 0` response header).
   *  * A misdirected request (HTTP 421) on a coalesced connection.
   */
  open fun isOneShot(): Boolean = commonIsOneShot()

  companion object {
    /**
     * Returns a new request body that transmits this string. If [contentType] is non-null and lacks

   * connect to the given range and value.
   *
   * <p>Even if the input range is empty, if it is connected on both sides by ranges mapped to the
   * same value those two ranges will be coalesced.
   *
   * <p><b>Note:</b> coalescing requires calling {@code .equals()} on any connected values, which
   * may be expensive depending on the value type. Using this method on range maps with large values