* this class separates _allocations_ from _streams_. An allocation is created by a call, used for
 * one or more streams, and then released. An allocated connection won't be stolen by other calls
 * while a redirect or authorization challenge is being handled.
 *
 * When the maximum concurrent streams limit is reduced, some allocations will be rescinded.

   * `allocations.size() < allocationLimit` then new streams can be created on this connection.
   */
  internal var allocationLimit = 1
    private set

  /** Current calls carried by this connection. */
  val calls = mutableListOf<Reference<RealCall>>()

  /** Timestamp when `allocations.size()` reached zero. Also assigned upon initial connection. */

     *
     * https://github.com/google/guava/issues/2254
     *
     * Other kinds of Errors are possible:
     *
     * - OutOfMemoryError from allocations in setFuture(): The calculus here is similar to
     * StackOverflowError: We can't reliably call setException(error).
     *
     * - Any kind of Error from a listener. Even if we could distinguish that case (by exposing some

     *
     * https://github.com/google/guava/issues/2254
     *
     * Other kinds of Errors are possible:
     *
     * - OutOfMemoryError from allocations in setFuture(): The calculus here is similar to
     * StackOverflowError: We can't reliably call setException(error).
     *
     * - Any kind of Error from a listener. Even if we could distinguish that case (by exposing some

      eventListener.callFailed(this, result!!)
    } else {
      eventListener.callEnd(this)
    }
    return result
  }

  /**
   * Remove this call from the connection's list of allocations. Returns a socket that the caller
   * should close.
   */
  internal fun releaseConnectionNoEvents(): Socket? {
    val connection = this.connection!!
    connection.assertLockHeld()

   * toIndex} exclusive. This is equivalent to {@code
   * Collections.rotate(Chars.asList(array).subList(fromIndex, toIndex), distance)}, but is
   * considerably faster and avoids allocations and garbage collection.
   *
   * <p>The provided "distance" may be negative, which will rotate left.
   *
   * @throws IndexOutOfBoundsException if {@code fromIndex < 0}, {@code toIndex > array.length}, or

   * toIndex} exclusive. This is equivalent to {@code
   * Collections.rotate(Shorts.asList(array).subList(fromIndex, toIndex), distance)}, but is
   * considerably faster and avoids allocations and garbage collection.
   *
   * <p>The provided "distance" may be negative, which will rotate left.
   *
   * @throws IndexOutOfBoundsException if {@code fromIndex < 0}, {@code toIndex > array.length}, or

   * toIndex} exclusive. This is equivalent to {@code
   * Collections.rotate(Shorts.asList(array).subList(fromIndex, toIndex), distance)}, but is
   * considerably faster and avoids allocations and garbage collection.
   *
   * <p>The provided "distance" may be negative, which will rotate left.
   *
   * @throws IndexOutOfBoundsException if {@code fromIndex < 0}, {@code toIndex > array.length}, or

   * toIndex} exclusive. This is equivalent to {@code
   * Collections.rotate(Ints.asList(array).subList(fromIndex, toIndex), distance)}, but is
   * considerably faster and avoids allocations and garbage collection.
   *
   * <p>The provided "distance" may be negative, which will rotate left.
   *
   * @throws IndexOutOfBoundsException if {@code fromIndex < 0}, {@code toIndex > array.length}, or

    /** The sequence number of the most recently committed edit to this entry. */
    internal var sequenceNumber: Long = 0

    init {
      // The names are repetitive so re-use the same builder to avoid allocations.
      val fileBuilder = StringBuilder(key).append('.')
      val truncateTo = fileBuilder.length
      for (i in 0 until valueCount) {
        fileBuilder.append(i)