docs: add sequence diagram to the aurora initial connection strategy plugin docs (#533)

Author: karenc-bq

docs/images/aurora_initial_connection_strategy.png

@@ -1,9 +1,17 @@
 # Aurora Initial Connection Strategy Plugin
-The Aurora Initial Connection Strategy Plugin allows users to configure their initial connection strategy, and it can also be used to obtain a connection more reliably if DNS is updating by replacing an out of date endpoint. When the Aurora Initial Connection Strategy Plugin attempts to make a connection, it may retry the connection attempt if there is a failure. Users are able to configure how often to retry a connection and the maximum allowed time to obtain a connection using the connection parameters.
+The Aurora Initial Connection Strategy Plugin allows users to configure their initial connection strategy, and it can also be used to obtain a connection more reliably if DNS is updating by replacing an out-of-date endpoint. 
 
-When this plugin is enabled, if the initial connection is to a reader cluster endpoint, the connected reader host will be chosen based on the configured strategy. The [initial connection strategy](../ReaderSelectionStrategies.md) specifies how the driver determines which available reader to connect to.
+The following sequence diagram describes the default plugin behaviour if no custom initial connection strategy is provided:
+<div style="text-align:center"><img src="../../images/aurora_initial_connection_strategy.png"/></div>
+The AWS Advanced Python Wrapper may retry the connection attempts multiple times until it is able to connect to a valid reader instance or a valid writer instance.
+You can configure how often to retry a connection and the maximum allowed time to obtain a connection using the `open_connection_retry_interval_ms` and the `open_connection_retry_timeout_ms` parameters respectively.
 
-This plugin also helps retrieve connections more reliably. When a user connects to a cluster endpoint, the actual instance for a new connection is resolved by DNS. During failover, the cluster elects another instance to be the writer. While DNS is updating, which can take up to 40-60 seconds, if a user tries to connect to the cluster endpoint, they may be connecting to an old host. This plugin helps by replacing the out of date endpoint if DNS is updating.
+When this plugin is enabled, if the initial connection is to a reader cluster endpoint, the connected reader host will be chosen based on selection strategy specified using the `reader_initial_connection_host_selector_strategy` parameter.
+See [initial connection strategy](../ReaderSelectionStrategies.md) for all possible strategies.
+
+This plugin also helps retrieve connections more reliably. When a user connects to a cluster endpoint, the actual instance for a new connection is resolved by DNS.
+During failover, the cluster elects another instance to be the writer. While DNS is updating, which can take up to 40-60 seconds, if a user tries to connect to the cluster endpoint, they may be connecting to an old host.
+This plugin helps by replacing the out of date endpoint if DNS is updating.
 
 ## Enabling the Aurora Initial Connection Strategy Plugin