async: Clarify difference between modparam("async","workers",x) and async_workers in core config

modules/async/README

@@ -38,7 +38,8 @@ Daniel-Constantin Mierla
    1.1. Set workers parameter
    1.2. async_route usage
    1.3. async_sleep usage
-   1.4. async_task_route usage
+   1.4. async_workers usage
+   1.5. async_task_route usage
 
 Chapter 1. Admin Guide
 
@@ -97,7 +98,7 @@ Chapter 1. Admin Guide
 3.1. workers (int)
 
    Number of worker processes to be started to handle the asynchronous
-   tasks.
+   tasks for async_route() and async_sleep().
 
    Default value is 1.
 
@@ -170,6 +171,16 @@ exit;
    The task is executed as soon as a process from asynchronous framework
    is idle, there is no wait time for the task like for async_route(...).
 
+   To enable the core asynchronous framework, you need to set the
+   async_workers core parameter in the configuration file. See the core
+   cookbook for more information.
+
+   Example 1.4. async_workers usage
+...
+; Enable 8 worker processes used by async and other modules
+async_workers=8
+...
+
    In case of internal errors, the function returns false, otherwise the
    function exits the execution of the script at that moment (return 0
    behaviour).
@@ -184,7 +195,7 @@ exit;
 
    This function can be used from REQUEST_ROUTE.
 
-   Example 1.4. async_task_route usage
+   Example 1.5. async_task_route usage
 ...
 async_task_route("RESUME");
 ...

modules/async/doc/async_admin.xml

@@ -70,7 +70,7 @@
 		<title><varname>workers</varname> (int)</title>
 		<para>
 			Number of worker processes to be started to handle the asynchronous
-			tasks.
+			tasks for async_route() and async_sleep(). 
 		</para>
 		<para>
 		<emphasis>
@@ -173,6 +173,20 @@ exit;
 		framework. The task is executed as soon as a process from asynchronous
 		framework is idle, there is no wait time for the task like for
 		async_route(...).
+		</para>
+		<para>
+		To enable the core asynchronous framework, you need to set the
+		<emphasis>async_workers</emphasis> core parameter in the configuration
+		file. See the core cookbook for more information.
+		<example>
+		<title><function>async_workers</function> usage</title>
+		<programlisting format="linespecific">
+...
+; Enable 8 worker processes used by async and other modules
+async_workers=8
+...
+</programlisting>
+	    </example>
 		</para>
 		<para>
 		In case of internal errors, the function returns false, otherwise the