Implement LLNDK for AVF

libavf will be a new LLNDK serving stable C APIs for AVF. For now it
supports creating a raw config, setting part of fields of raw configs,
spawning/connecting to virtmgr, and then creating a VM.

Bug: 369588412
Test: run a VM with libavf
Change-Id: If0ef5ec4e4121a872e65e862698f674e0352c372
diff --git a/libs/libvmclient/src/lib.rs b/libs/libvmclient/src/lib.rs
index 13630c0..c0baea5 100644
--- a/libs/libvmclient/src/lib.rs
+++ b/libs/libvmclient/src/lib.rs
@@ -243,6 +243,11 @@
         self.vm.start()
     }
 
+    /// Stops the VM.
+    pub fn stop(&self) -> BinderResult<()> {
+        self.vm.stop()
+    }
+
     /// Returns the CID used for vsock connections to the VM.
     pub fn cid(&self) -> i32 {
         self.cid