added a configuration example to the readme file

Author: gregory-at-cvs

instrumentation/sessions/README.md

@@ -12,6 +12,25 @@ for additional details about sessions.
 See ["Session Events"](https://github.com/open-telemetry/semantic-conventions/blob/main/docs/general/session.md#session-events)
 for more information about the specific events generated by this instrumentation.
 
+## Configuration
+
+When using the [android agent](../../android-agent), sessions work out of the box with sensible defaults.
+You can customize session behavior using the configuration DSL:
+
+```kotlin
+OpenTelemetryRumInitializer.initialize(context) {
+    session {
+        // Session expires after 15 minutes in background (default)
+        backgroundInactivityTimeout = 15.minutes
+
+        // Session expires after 4 hours regardless of activity (default)
+        maxLifetime = 4.hours
+    }
+}
+```
+
+If not using the agent, you can create a `SessionManager` directly with a custom `SessionConfig`.
+
 ## Installation
 
 This instrumentation comes with the [android agent](../../android-agent) out of the box, so