observability: tracing gum, automatically cross ref traceID (#5079)

* add some gum

* bump expander

* gum

* fix all remaining issues

* last fixup

* Update node/gum/proc-macro/src/lib.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* change

* netowrk

* fixins

* chore

* allow optional fmt str + args, prep for expr as kv field

* tracing -> gum rename fallout

* restrict further

* allow multiple levels of field accesses

* another round of docs and a slip of the pen

* update ADR

* fixup lock fiel

* use target: instead of target=

* minors

* fix

* chore

* Update node/gum/README.md

Co-authored-by: Andrei Sandu <54316454+sandreim@users.noreply.github.com>

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>
Co-authored-by: Andrei Sandu <54316454+sandreim@users.noreply.github.com>

polkadot/node/core/bitfield-signing/src/lib.rs

@@ -106,7 +106,7 @@ async fn get_core_availability(
 
 		let res = rx.await.map_err(Into::into);
 
-		tracing::trace!(
+		gum::trace!(
 			target: LOG_TARGET,
 			para_id = %core.para_id(),
 			availability = ?res,
@@ -172,7 +172,7 @@ async fn construct_availability_bitfield(
 	.await?;
 
 	let core_bits = FromIterator::from_iter(results.into_iter());
-	tracing::debug!(
+	gum::debug!(
 		target: LOG_TARGET,
 		?relay_parent,
 		"Signing Bitfield for {core_count} cores: {core_bits}",
@@ -247,7 +247,7 @@ impl JobTrait for BitfieldSigningJob {
 		let metrics = metrics.clone();
 		async move {
 			if let LeafStatus::Stale = leaf.status {
-				tracing::debug!(
+				gum::debug!(
 					target: LOG_TARGET,
 					hash = ?leaf.hash,
 					block_number =  ?leaf.number,
@@ -288,7 +288,7 @@ impl JobTrait for BitfieldSigningJob {
 			{
 				Err(Error::Runtime(runtime_err)) => {
 					// Don't take down the node on runtime API errors.
-					tracing::warn!(target: LOG_TARGET, err = ?runtime_err, "Encountered a runtime API error");
+					gum::warn!(target: LOG_TARGET, err = ?runtime_err, "Encountered a runtime API error");
 					return Ok(())
 				},
 				Err(err) => return Err(err),
@@ -305,7 +305,7 @@ impl JobTrait for BitfieldSigningJob {
 			{
 				Some(b) => b,
 				None => {
-					tracing::error!(
+					gum::error!(
 						target: LOG_TARGET,
 						"Key was found at construction, but while signing it could not be found.",
 					);