libpthread-workqueue0 binary package in Ubuntu Focal i386

 The pthread_workqueue library allows you to create one or more workqueues
 and submit work items for processing. The workqueues are serviced by a
 thread pool that is automatically created and dynamically managed by the
 library.
 .
 The API is based on the pthread_workqueue API in FreeBSD 8.0, which was
 designed to be compatible with the API developed by Apple Inc to support
 the Grand Central Dispatch concurrency framework.