Add NetworkCallback#onReserved

onReserved() is called in response to a successful Network reservation
with the NetworkCapabilities of the reserved network. onReserved is
called at most once. If the reservation is released, onUnavailable is
called.

Test: TH
API-Coverage-Bug: 372936361
Change-Id: Idcef572ab9d07981799efc349206aadb620e0e69
diff --git a/framework/api/current.txt b/framework/api/current.txt
index 7bc0cf3..32dcfd9 100644
--- a/framework/api/current.txt
+++ b/framework/api/current.txt
@@ -151,6 +151,7 @@
     method public void onLinkPropertiesChanged(@NonNull android.net.Network, @NonNull android.net.LinkProperties);
     method public void onLosing(@NonNull android.net.Network, int);
     method public void onLost(@NonNull android.net.Network);
+    method @FlaggedApi("com.android.net.flags.ipv6_over_ble") public void onReserved(@NonNull android.net.NetworkCapabilities);
     method public void onUnavailable();
     field public static final int FLAG_INCLUDE_LOCATION_INFO = 1; // 0x1
   }