Print callback results to stderr am: 8dbc322981

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Virtualization/+/1814904

Change-Id: If1a6f0d0ba61688230017cbe24b414d67663abab
diff --git a/vm/src/run.rs b/vm/src/run.rs
index 4b656ae..ccb4085 100644
--- a/vm/src/run.rs
+++ b/vm/src/run.rs
@@ -190,10 +190,12 @@
     }
 
     fn onPayloadReady(&self, _cid: i32) -> BinderResult<()> {
+        eprintln!("payload is ready");
         Ok(())
     }
 
-    fn onPayloadFinished(&self, _cid: i32, _exit_code: i32) -> BinderResult<()> {
+    fn onPayloadFinished(&self, _cid: i32, exit_code: i32) -> BinderResult<()> {
+        eprintln!("payload finished with exit code {}", exit_code);
         Ok(())
     }