agent: log RPC calls for debugging

We can log all RPC calls to the agent for debugging purposes
to check which RPC is called, which can help us to understand
the container lifespan.

Fixes: #4738

Signed-off-by: liubin <liubin0329@gmail.com>

src/agent/src/tracer.rs

@@ -69,6 +69,8 @@ macro_rules! trace_rpc_call {
             propagator.extract(&extract_carrier_from_ttrpc($ctx))
         });
 
+        info!(sl!(), "rpc call from shim to agent: {:?}", $name);
+
         // generate tracing span
         let rpc_span = span!(tracing::Level::INFO, $name, "mod"="rpc.rs", req=?$req);