Update wording and add exposures through segment docs

Author: marcioapm

src/connections/destinations/catalog/actions-absmartly/index.md

@@ -20,7 +20,8 @@ This destination is maintained by ABsmartly. For any issues with the destination
 3. Add the following Connection Settings:
    - **Collector Endpoint**: Your ABsmartly Collector REST Endpoint. Usually `https://<your-subdomain>.absmartly.io/v1`
    - **API Key**: An existing API Key. Created under Settings->API Keys in the ABsmartly Web Console.
-   - **Environment**: The environment where the events are originated matching an existing environment in ABsmartly. Created under Settings->Environments in the ABsmartly Web Console. 
+   - **Environment**: The environment where the events are originated matching an existing environment in ABsmartly. Created under Settings->Environments in the ABsmartly Web Console.
+5. Enable the _Track Calls_ mapping to send events to ABsmartly.
 
 {% include components/actions-fields.html %}
 
@@ -34,7 +35,7 @@ other destinations. The Segment spec includes the [Experiment Viewed semantic ev
 for this purpose.
 
 > info ""
-> By default, the _Track Calls_ action will filter and not send to ABsmartly events with name `Experiment Viewed`.
+> By default, the _Track Calls_ mapping will filter and not send to ABsmartly events with name `Experiment Viewed`.
 
 In the ABsmartly context, we can [install a custom event logger](https://docs.absmartly.com/docs/sdk%20documentation/getting-started/#using-a-custom-event-logger) and send exposures directly to Segment.
 
@@ -75,6 +76,91 @@ analytics.ready(function() {
 });
 ```
 
+### Publishing experiment exposures through Segment
+
+To publish experiment exposures through Segment, you must first configure
+and enable the _Exposures (Verbatim)_ mapping on your ABsmartly (Actions) destination.
+
+We want to replace the direct flow of exposure events from the ABsmartly SDK to the ABsmartly collector, by instead sending them to Segment
+for processing by the destination function.
+
+This can be achieved by instantiating the ABsmartly SDK with a custom context publisher.
+
+The custom publisher will publish an `Experiment Viewed` Segment event with ABsmartly's exposure data in the `properties.exposure` field as well
+as the normal semantic data that Segment recommends for this event.
+
+Here is an example in Javascript.
+
+```javascript
+analytics.ready(function() {
+    // initialize ABSmartly SDK
+    const sdk = new absmartly.SDK({
+        endpoint: 'https://your-absmartly-endpoint.absmartly.io/v1',
+        apiKey: '<YOUR-API-KEY>',
+        environment: 'development',
+        application: 'YOUR-APP',
+    });
+
+    // ABSmartly publisher implementation that publishes ABSmartly exposures to Segment,
+    // instead of directly to the ABSmartly Collector
+    // these will then be pushed by the ABSmartly segment integration to the ABSmartly collector
+    class SegmentContextPublisher extends absmartly.ContextPublisher {
+        constructor(segment) {
+            super();
+
+            this._segment = segment;
+        }
+
+        publish(request, sdk, context) {
+            // NOTE: only exposures are expected to come via this route
+            // other types of events should be tracked through the Segment API
+            if (request.exposures) {
+                for (const exposure of request.exposures) {
+                    this._segment.track(`Experiment Viewed`, {
+                        experiment_id: exposure.id,
+                        experiment_name: exposure.name,
+                        variation_id: exposure.variant,
+                        variation_name: "ABCDEFG"[exposure.variant],
+                        exposure: Object.assign({},
+                            {
+                                exposures: [exposure],
+                            },
+                            // add anything else in the a/b smartly payload that are not exposures or goals
+                            ...Object.entries(request)
+                                .filter(e => (e[0] !== 'exposures') && (e[0] !== 'goals'))
+                                .map(e => ({[e[0]]: e[1]}))
+                        )
+                    });
+                }
+            }
+
+            return Promise.resolve();
+        }
+    }
+
+    // set this as the default publisher - all contexts created from now on will use it by default
+    sdk.setContextPublisher(new SegmentContextPublisher(analytics));
+
+    const request = {
+        units: {
+            userId: analytics.user().id(),
+            anonymousId: analytics.user().anonymousId(),
+        },
+    };
+
+    window.context = sdk.createContext(request);
+    context.attribute("user_agent", navigator.userAgent);
+
+    context.ready().then((response) => {
+        console.log("ABSmartly Context ready!");
+        console.log(context.treatment("test-exp"));
+    }).catch((error) => {
+        console.log(error);
+    });
+});
+```
+
+
 ## Migration from the classic A/B Smartly destination
 
 To migrate from the classic A/B Smartly destination to ABsmartly (Actions) be sure to disconnect the classic A/B Smartly destination before enabling the ABsmartly (Actions) destination to avoid duplicate experimentation events in ABsmartly.