DOCSP-45870 - Parallelism note (#379)

(cherry picked from commit 5a7520f)

Author: mongoKart

source/fundamentals/transactions.txt

@@ -199,6 +199,15 @@ through the following steps:
 
       Successfully committed transaction!
 
+.. sharedinclude:: dbx/transactions-parallelism.rst
+
+   .. replacement:: driver-specific-content
+
+      If you're using {+mdb-server+} v8.0 or later, you can perform
+      write operations on multiple namespaces within a single transaction by using
+      the ``BulkWrite()`` or ``BulkWriteAsync()`` method. For more information,
+      see :ref:`<csharp-bulk-write>`.
+
 Additional Information
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