Explain how to associate RequestFinishedInfo with original request

components/cronet/android/api/src/org/chromium/net/RequestFinishedInfo.java

Index: components/cronet/android/api/src/org/chromium/net/RequestFinishedInfo.java
diff --git a/components/cronet/android/api/src/org/chromium/net/RequestFinishedInfo.java b/components/cronet/android/api/src/org/chromium/net/RequestFinishedInfo.java
index fcc6032d07de95cd17be998539313c4f6768315e..570738feeaedfdd8ce6b2baf547f6692427838d7 100644
--- a/components/cronet/android/api/src/org/chromium/net/RequestFinishedInfo.java
+++ b/components/cronet/android/api/src/org/chromium/net/RequestFinishedInfo.java
@@ -13,6 +13,12 @@ import java.util.concurrent.Executor;
 /**
  * Information about a finished request. Passed to {@link RequestFinishedInfo.Listener}.
  *
+ * To associate the data with the original request, use
+ * {@link ExperimentalUrlRequest.Builder#addRequestAnnotation} or
+ * {@link ExperimentalBidirectionalStream.Builder#addRequestAnnotation} to add a unique identifier
+ * when creating the request, and call {@link #getAnnotations} when the {@link RequestFinishedInfo}
+ * is received to retrieve the identifier.
+ *
  * {@hide} as it's a prototype.
  */
 public abstract class RequestFinishedInfo {
@@ -257,11 +263,22 @@ public abstract class RequestFinishedInfo {
      */
     public static final int CANCELED = 2;
 
-
-    /** Returns the request's original URL. */
+    /**
+     * Returns the request's original URL.
+     *
+     * @return the request's original URL
+     */
     public abstract String getUrl();
 
-    /** Returns the objects that the caller has supplied when initiating the request. */
+    /**
+     * Returns the objects that the caller has supplied when initiating the request, using
+     * {@link ExperimentalUrlRequest.Builder#addRequestAnnotation} or
+     * {@link ExperimentalBidirectionalStream.Builder#addRequestAnnotation}.
+     * Annotations can be used to associate a {@link RequestFinishedInfo} with the original request
+     * or type of request.
+     *
+     * @return annotations supplied when creating the request
+     */
     public abstract Collection<Object> getAnnotations();
 
     // TODO(klm): Collect and return a chain of Metrics objects for redirect responses.