apkverify: signature verification over signed data

Bug: 190343842
Test: MicrodroidHostTestCases
Change-Id: I130daa50995f30b3a2315a46d8d2f743d20ed0f2
diff --git a/apkverify/src/bytes_ext.rs b/apkverify/src/bytes_ext.rs
index 61848ad..5efb33c 100644
--- a/apkverify/src/bytes_ext.rs
+++ b/apkverify/src/bytes_ext.rs
@@ -20,7 +20,7 @@
 use bytes::{Buf, Bytes};
 use std::ops::Deref;
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct LengthPrefixed<T> {
     inner: T,
 }