* of reads may not be immediately reflected on the algorithm's data structures. These structures
   * are guarded by a lock and operations are applied in batches to avoid lock contention. The
   * penalty of applying the batches is spread across threads so that the amortized cost is slightly
   * higher than performing just the operation without enforcing the capacity constraint.
   *

  protected AbstractFuture() {}

  // Gets and Timed Gets
  //
  // * Be responsive to interruption
  // * Don't create Waiter nodes if you aren't going to park, this helps reduce contention on the
  //   waiters field.
  // * Future completion is defined by when #value becomes non-null/non SetFuture
  // * Future completion can be observed if the waiters field contains a TOMBSTONE

  // Timed Get