obox: azure: Add debugging instructions

source/configuration_manual/mail_location/obox/azure.rst

@@ -22,3 +22,25 @@ The parameters are:
 +=================================+==========================================================+
 | See :ref:`http_storages` for common parameters                                             |
 +---------------------------------+----------------------------------------------------------+
+
+
+Debugging
+---------
+
+To be able to easily track requests outgoing from Dovecot and incoming from
+the Azure storage the following headers should be added as `loghdr` (For more
+details see :ref:`http_storages`)
+
+.. code-block:: none
+
+  plugin {
+  # Debugging configuration:
+     obox_fs = azure:https://ACCOUNTNAME:[email protected]/?loghdr=x-ms-client-request-id&loghdr=x-ms-request-id
+   }
+
+This configuration makes sure that the ``x-ms-client-request-id`` header is
+added to the requests by Dovecot. This will use the current session id, which
+allows to correlate Dovecot activities with requests that the server
+receives. Additionally the ``x-ms-request-id`` header should be added as
+loghdr as well. This header is added by the Azure storage to identify
+individual requests.