DOCSP-39027: Add CMAP diagram to FAQ page (#192)

Author: mcmorisi

source/faq.txt

@@ -44,7 +44,11 @@ support concurrent MongoDB operations in your multi-threaded application.
 The maximum size of each connection pool is set by the ``MaxConnectionPoolSize`` option, which
 defaults to ``100``. If the number of in-use connections to a server reaches
 the value of ``MaxConnectionPoolSize``, the next request to that server will wait
-until a connection becomes available.
+until a connection becomes available. The following diagram illustrates a high-level view
+of how the ``MongoClient`` manages a connection pool:
+
+.. figure:: /includes/figures/CMAP_diagram.svg
+   :alt: CMAP diagram
 
 In addition to the sockets needed to support your application's threads,
 each ``MongoClient`` instance opens two additional sockets per server