feat(studyPrefetcher): Study Prefetcher (#4206)

platform/docs/docs/configuration/configurationFiles.md

@@ -258,6 +258,35 @@ This will result in two panels, one with `dicomSeg.panel` and `tracked.measureme
 
 :::
 
+### Study Prefetcher
+
+You can enable the study prefetcher so that OHIF loads the next/previous series/display sets
+based on the proximity to the current series/display set. This can be useful to improve the user experience
+
+
+```js
+  studyPrefetcher: {
+    /* Enable/disable study prefetching service (default: false) */
+    enabled: true,
+    /* Number of displaysets to be prefetched  (default: 2)*/
+    displaySetCount: 2,
+    /**
+     * Max number of concurrent prefetch requests (default: 10)
+     * High numbers may impact on the time to load a new dropped series because
+     * the browser will be busy with all prefetching requests. As soon as the
+     * prefetch requests get fulfilled the new ones from the new dropped series
+     * are sent to the server.
+     *
+     * TODO: abort all prefetch requests when a new series is loaded on a viewport.
+     * (need to add support for `AbortController` on Cornerstone)
+     * */
+    maxNumPrefetchRequests: 10,
+    /* Display sets loading order (closest (deafult), downward or upward) */
+    order: 'closest',
+  },
+
+```
+
 ### More on Accept Header Configuration
 In the previous section we showed that you can modify the `acceptHeader`
 configuration to request specific dicom transfer syntax. By default

platform/docs/docs/migration-guide/from-v2.md

@@ -102,7 +102,7 @@ There are various configurations available to customize the viewer. Each configu
 OHIF v3 has a new configuration structure. The main difference is that the `servers` is renamed to `dataSources` and the configuration is now asynchronous. Datasources are more abstract and
 far more capable than servers. Read more about dataSources [here](../platform/extensions/modules/data-source.md).
 
-- `StudyPrefetcher` is not currently supported in OHIF v3.
+- `StudyPrefetcher` is only available in OHIF v3.9 beta and will be available in the next stable 3.9 release.
 - The `servers` object has been replaced with a `dataSources` array containing objects representing different data sources.
 - The cornerstoneExtensionConfig property has been removed, you should use `customizationService` instead (you can read more [here](../platform/services/ui/customization-service.md))
 - The maxConcurrentMetadataRequests property has been removed in favor of `maxNumRequests`