node: Add debug messages when building halo2 keys.

src/node/client.rs

@@ -221,10 +221,12 @@ impl Client {
     }
 
     fn build_mint_pk() -> ProvingKey {
+        debug!("Building proving key for MintContract");
         ProvingKey::build(11, &MintContract::default())
     }
 
     fn build_burn_pk() -> ProvingKey {
+        debug!("Building proving key for BurnContract");
         ProvingKey::build(11, &BurnContract::default())
     }
 }

src/node/state.rs

@@ -226,9 +226,11 @@ impl ProgramState for State {
 }
 
 fn build_mint_vk() -> VerifyingKey {
+    debug!("Building verifying key for MintContract");
     VerifyingKey::build(11, &MintContract::default())
 }
 
 fn build_burn_vk() -> VerifyingKey {
+    debug!("Building verifying key for BurnContract");
     VerifyingKey::build(11, &BurnContract::default())
 }