diff --git a/Subtrees/beast/modules/beast_basics/threads/beast_Workers.cpp b/Subtrees/beast/modules/beast_basics/threads/beast_Workers.cpp
index b4fa54ec9..81b956121 100644
--- a/Subtrees/beast/modules/beast_basics/threads/beast_Workers.cpp
+++ b/Subtrees/beast/modules/beast_basics/threads/beast_Workers.cpp
@@ -96,6 +96,8 @@ void Workers::pauseAllThreadsAndWait ()
     setNumberOfThreads (0);
 
     m_allPaused.wait ();
+
+    bassert (numberOfCurrentlyRunningTasks () == 0);
 }
 
 void Workers::addTask ()
@@ -103,6 +105,11 @@ void Workers::addTask ()
     m_semaphore.signal ();
 }
 
+int Workers::numberOfCurrentlyRunningTasks () const noexcept
+{
+    return m_runningTaskCount.get ();
+}
+
 void Workers::deleteWorkers (LockFreeStack <Worker>& stack)
 {
     for (;;)
@@ -176,7 +183,9 @@ void Workers::Worker::run ()
             // We couldn't pause so we must have gotten
             // unblocked in order to process a task.
             //
+            ++m_workers.m_runningTaskCount;
             m_workers.m_callback.processTask ();
+            --m_workers.m_runningTaskCount;
         }
 
         // Any worker that goes into the paused list must
diff --git a/Subtrees/beast/modules/beast_basics/threads/beast_Workers.h b/Subtrees/beast/modules/beast_basics/threads/beast_Workers.h
index 4d2d9e9a9..f7be8f67d 100644
--- a/Subtrees/beast/modules/beast_basics/threads/beast_Workers.h
+++ b/Subtrees/beast/modules/beast_basics/threads/beast_Workers.h
@@ -29,7 +29,12 @@ public:
     struct Callback
     {
         /** Perform a task.
-            The call is made on a thread owned by Workers.
+
+            The call is made on a thread owned by Workers. It is important
+            that you only process one task from inside your callback. Each
+            call to addTask will result in exactly one call to processTask.
+
+            @see Workers::addTask
         */
         virtual void processTask () = 0;
     };
@@ -68,12 +73,22 @@ public:
     */
     void pauseAllThreadsAndWait ();
 
-    /** Increment the number of tasks.
-        The callback will be called for each task.
+    /** Add a task to be performed.
+
+        Every call to addTask will eventually result in a call to
+        Callback::processTask unless the Workers object is destroyed or
+        the number of threads is never set above zero.
+
         @note This function is thread-safe.
     */
     void addTask ();
 
+    /** Get the number of currently executing calls of Callback::processTask.
+        While this function is thread-safe, the value may not stay
+        accurate for very long. It's mainly for diagnostic purposes.
+    */
+    int numberOfCurrentlyRunningTasks () const noexcept;
+
     //--------------------------------------------------------------------------
 
 private:
@@ -87,7 +102,6 @@ private:
         Idle:   Active, but blocked on waiting for a task.
         Pausd:  Blocked waiting to exit or become active.
     */
-
     class Worker
         : public LockFreeStack <Worker>::Node
         , public LockFreeStack <Worker, PausedTag>::Node
@@ -115,6 +129,7 @@ private:
     int m_numberOfThreads;                       // how many we want active now
     Atomic <int> m_activeCount;                  // to know when all are paused
     Atomic <int> m_pauseCount;                   // how many threads need to pause now
+    Atomic <int> m_runningTaskCount;             // how many calls to processTask() active
     LockFreeStack <Worker> m_everyone;           // holds all created workers
     LockFreeStack <Worker, PausedTag> m_paused;  // holds just paused workers
 };