o Major features:
    - Refactor the CPU worker implementation for better performance by
      avoiding the kernel and lengthening pipelines. The original
      implementation used sockets to transfer data from the main thread
      to the worker threads, and didn't allow any thread to be assigned
      more than a single piece of work at once. The new implementation
      avoids communications overhead by making requests in shared
      memory, avoiding kernel IO where possible, and keeping more
      request in flight at once. Resolves issue #9682.