fix(cli): Add traces to clarify where time is going

In looking at the traces, I had a couple of questions of where the time
is going, like
- Why does writing a package file take so long
- How much of manifest parsing is TOML parsing vs target discovery vs
  other stuff


This adds traces to help answer those.

Author: epage

src/cargo/core/resolver/encode.rs

@@ -637,6 +637,7 @@ impl<'de> de::Deserialize<'de> for EncodablePackageId {
 }
 
 impl ser::Serialize for Resolve {
+    #[tracing::instrument(skip_all)]
     fn serialize<S>(&self, s: S) -> Result<S::Ok, S::Error>
     where
         S: ser::Serializer,

src/cargo/core/summary.rs

@@ -31,6 +31,7 @@ struct Inner {
 }
 
 impl Summary {
+    #[tracing::instrument(skip_all)]
     pub fn new(
         pkg_id: PackageId,
         dependencies: Vec<Dependency>,

src/cargo/ops/lockfile.rs

@@ -112,6 +112,7 @@ fn resolve_to_string_orig(
     (orig.ok(), out, lock_root)
 }
 
+#[tracing::instrument(skip_all)]
 fn serialize_resolve(resolve: &Resolve, orig: Option<&str>) -> String {
     let toml = toml::Table::try_from(resolve).unwrap();
 
@@ -194,6 +195,7 @@ fn serialize_resolve(resolve: &Resolve, orig: Option<&str>) -> String {
     out
 }
 
+#[tracing::instrument(skip_all)]
 fn are_equal_lockfiles(orig: &str, current: &str, ws: &Workspace<'_>) -> bool {
     // If we want to try and avoid updating the lock file, parse both and
     // compare them; since this is somewhat expensive, don't do it in the

src/cargo/util/toml/mod.rs

@@ -424,6 +424,7 @@ pub fn prepare_for_publish(
     }
 }
 
+#[tracing::instrument(skip_all)]
 pub fn to_real_manifest(
     me: manifest::TomlManifest,
     embedded: bool,
@@ -723,6 +724,7 @@ pub fn to_real_manifest(
         root: package_root,
     };
 
+    #[tracing::instrument(skip(manifest_ctx, new_deps, workspace_config, inherit_cell))]
     fn process_dependencies(
         manifest_ctx: &mut ManifestContext<'_, '_>,
         new_deps: Option<&BTreeMap<manifest::PackageName, manifest::InheritableDependency>>,
@@ -1531,6 +1533,7 @@ fn default_readme_from_package_root(package_root: &Path) -> Option<String> {
 
 /// Checks a list of build targets, and ensures the target names are unique within a vector.
 /// If not, the name of the offending build target is returned.
+#[tracing::instrument(skip_all)]
 fn unique_build_targets(
     targets: &[Target],
     package_root: &Path,

src/cargo/util/toml/targets.rs

@@ -32,6 +32,7 @@ const DEFAULT_BENCH_DIR_NAME: &'static str = "benches";
 const DEFAULT_EXAMPLE_DIR_NAME: &'static str = "examples";
 const DEFAULT_BIN_DIR_NAME: &'static str = "bin";
 
+#[tracing::instrument(skip_all)]
 pub(super) fn targets(
     features: &Features,
     manifest: &TomlManifest,