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/overseer/src/dummy.rs

@@ -43,7 +43,7 @@ where
 					Err(_) => return Ok(()),
 					Ok(FromOverseer::Signal(OverseerSignal::Conclude)) => return Ok(()),
 					Ok(overseer_msg) => {
-						tracing::debug!(
+						gum::debug!(
 							target: "dummy-subsystem",
 							"Discarding a message sent from overseer {:?}",
 							overseer_msg

polkadot/node/overseer/src/lib.rs

@@ -199,7 +199,7 @@ impl Handle {
 	/// Most basic operation, to stop a server.
 	async fn send_and_log_error(&mut self, event: Event) {
 		if self.0.send(event).await.is_err() {
-			tracing::info!(target: LOG_TARGET, "Failed to send an event to Overseer");
+			gum::info!(target: LOG_TARGET, "Failed to send an event to Overseer");
 		}
 	}
 }
@@ -529,21 +529,18 @@ where
 			Ok(memory_stats) =>
 				Box::new(move |metrics: &OverseerMetrics| match memory_stats.snapshot() {
 					Ok(memory_stats_snapshot) => {
-						tracing::trace!(
+						gum::trace!(
 							target: LOG_TARGET,
 							"memory_stats: {:?}",
 							&memory_stats_snapshot
 						);
 						metrics.memory_stats_snapshot(memory_stats_snapshot);
 					},
-					Err(e) => tracing::debug!(
-						target: LOG_TARGET,
-						"Failed to obtain memory stats: {:?}",
-						e
-					),
+					Err(e) =>
+						gum::debug!(target: LOG_TARGET, "Failed to obtain memory stats: {:?}", e),
 				}),
 			Err(_) => {
-				tracing::debug!(
+				gum::debug!(
 					target: LOG_TARGET,
 					"Memory allocation tracking is not supported by the allocator.",
 				);
@@ -634,7 +631,7 @@ where
 					}
 				},
 				res = self.running_subsystems.select_next_some() => {
-					tracing::error!(
+					gum::error!(
 						target: LOG_TARGET,
 						subsystem = ?res,
 						"subsystem finished unexpectedly",