Improve documentation on start_background_task() function

src/socketio/asyncio_client.py

@@ -311,9 +311,7 @@ class AsyncClient(client.Client):
         :param args: arguments to pass to the function.
         :param kwargs: keyword arguments to pass to the function.
 
-        This function returns an object compatible with the `Thread` class in
-        the Python standard library. The `start()` method on this object is
-        already called by this function.
+        The return value is a ``asyncio.Task`` object.
         """
         return self.eio.start_background_task(target, *args, **kwargs)
 

src/socketio/asyncio_server.py

@@ -396,8 +396,6 @@ class AsyncServer(server.Server):
         :param kwargs: keyword arguments to pass to the function.
 
         The return value is a ``asyncio.Task`` object.
-
-        Note: this method is a coroutine.
         """
         return self.eio.start_background_task(target, *args, **kwargs)
 

src/socketio/client.py

@@ -500,9 +500,9 @@ class Client(object):
         :param args: arguments to pass to the function.
         :param kwargs: keyword arguments to pass to the function.
 
-        This function returns an object compatible with the `Thread` class in
-        the Python standard library. The `start()` method on this object is
-        already called by this function.
+        This function returns an object that represents the background task,
+        on which the ``join()`` methond can be invoked to wait for the task to
+        complete.
         """
         return self.eio.start_background_task(target, *args, **kwargs)
 

src/socketio/server.py

@@ -599,9 +599,9 @@ class Server(object):
         :param args: arguments to pass to the function.
         :param kwargs: keyword arguments to pass to the function.
 
-        This function returns an object compatible with the `Thread` class in
-        the Python standard library. The `start()` method on this object is
-        already called by this function.
+        This function returns an object that represents the background task,
+        on which the ``join()`` methond can be invoked to wait for the task to
+        complete.
         """
         return self.eio.start_background_task(target, *args, **kwargs)