Oct 31, 2016 · Oct 31, 2016 · Nov 2, 2016
diff --git a/email/spool.rst b/email/spool.rst
 Of course you will not want to run this manually in reality. Instead, the
 console command should be triggered by a cron job or scheduled task and run
 at a regular interval.

 .. caution::

    When you create a message with SwiftMailer, it generates a ``Swift_Message``
    class. If the ``swiftmailer`` service is lazy loaded, it generates instead a
    proxy class named ``Swift_Message_<someRandomCharacters>``.

    If you use the memory spool, this change is transparent and has no impact.
    But when using the filesystem spool, the message class is serialized in
    a file with the randomized class name. The problem is that this random
    class name changes on every cache clear. So if you send a mail and then you
    clear the cache, the message will not be unserializable.

    On the next execution of ``swiftmailer:spool:send`` an error will raise because
    the class ``Swift_Message_<someRandomCharacters>`` doesn't exist (anymore).

    The solutions are either to use the memory spool or to load the
    ``swiftmailer`` service without ``lazy`` option (see :doc:`/service_container/lazy_services`).
Original file line number	Diff line number	Diff line change
Expand Up		@@ -141,3 +141,21 @@ You can also set the time limit in seconds:
		Of course you will not want to run this manually in reality. Instead, the
		console command should be triggered by a cron job or scheduled task and run
		at a regular interval.

		.. caution::

		When you create a message with SwiftMailer, it generates a ``Swift_Message``
		class. If the ``swiftmailer`` service is lazy loaded, it generates instead a
		proxy class named ``Swift_Message_<someRandomCharacters>``.

		If you use the memory spool, this change is transparent and has no impact.
		But when using the filesystem spool, the message class is serialized in
		a file with the randomized class name. The problem is that this random
		class name changes on every cache clear. So if you send a mail and then you
		clear the cache, the message will not be unserializable.

		On the next execution of ``swiftmailer:spool:send`` an error will raise because
		the class ``Swift_Message_<someRandomCharacters>`` doesn't exist (anymore).

		The solutions are either to use the memory spool or to load the
		``swiftmailer`` service without ``lazy`` option (see :doc:`/service_container/lazy_services`).