Merge branch '4.2'

* 4.2:
  [Messenger] Collect all stamps added on Envelope

Author: javiereguiluz

components/messenger.rst

@@ -174,9 +174,15 @@ Hence you can inspect the envelope content and its stamps, or add any::
         }
     }
 
-The above example will forward the message to the next middleware with an additional
-stamp *if* the message has just been received (i.e. has the `ReceivedStamp` stamp).
-You can create your own stamps by implementing :class:`Symfony\\Component\\Messenger\\Stamp\\StampInterface`.
+The above example will forward the message to the next middleware with an
+additional stamp *if* the message has just been received (i.e. has at least one
+``ReceivedStamp`` stamp). You can create your own stamps by implementing
+:class:`Symfony\\Component\\Messenger\\Stamp\\StampInterface`.
+
+If you want to examine all stamps on an envelope, use the ``$envelope->all()``
+method, which returns all stamps grouped by type (FQCN). Alternatively, you can
+iterate through all stamps of a specific type by using the FQCN as first
+parameter of this method (e.g. ``$envelope->all(ReceivedStamp::class)``).
 
 .. note::