Use tracing for logging. (#29)

This commit updates how logging is done in the differential testing
harness to use `tracing` instead of using the `log` crate. This allows
us to be able to better associate logs with the cases being executed
which makes it easier to debug and understand what the harness is doing.

crates/node/src/geth.rs

@@ -159,7 +159,7 @@ impl EthereumNode for Instance {
         let connection_string = self.connection_string();
         let wallet = self.wallet.clone();
 
-        log::debug!("Submitting transaction: {transaction:#?}");
+        tracing::debug!("Submitting transaction: {transaction:#?}");
 
         execute_transaction(Box::pin(async move {
             Ok(ProviderBuilder::new()

crates/node/src/kitchensink.rs

@@ -252,7 +252,7 @@ impl EthereumNode for KitchensinkNode {
         let url = self.rpc_url.clone();
         let wallet = self.wallet.clone();
 
-        log::debug!("Submitting transaction: {transaction:#?}");
+        tracing::debug!("Submitting transaction: {transaction:#?}");
 
         execute_transaction(Box::pin(async move {
             Ok(ProviderBuilder::new()

crates/node/src/pool.rs

@@ -62,7 +62,7 @@ where
 
 fn spawn_node<T: Node + Send>(args: &Arguments, genesis: String) -> anyhow::Result<T> {
     let mut node = T::new(args);
-    log::info!("starting node: {}", node.connection_string());
+    tracing::info!("starting node: {}", node.connection_string());
     node.spawn(genesis)?;
     Ok(node)
 }