Add telemetry for scrobble rule application

lib/music_library/scrobble_rules.ex

@@ -336,6 +336,8 @@ defmodule MusicLibrary.ScrobbleRules do
 
   """
   def apply_all_rules do
+    :telemetry.span([:music_library, :scrobble_rules, :apply_all_rules], %{}, fn ->
+      result =
         list_enabled_rules()
         |> Enum.map(fn rule ->
           case apply_rule(rule) do
@@ -343,6 +345,9 @@ defmodule MusicLibrary.ScrobbleRules do
             {:error, reason} -> {:error, {rule.type, rule.match_value, reason}}
           end
         end)
+
+      {result, %{scrobble_track_count: :all}}
+    end)
   end
 
   @doc """
@@ -362,6 +367,8 @@ defmodule MusicLibrary.ScrobbleRules do
   end
 
   def apply_all_rules(tracks) do
+    :telemetry.span([:music_library, :scrobble_rules, :apply_all_rules], %{}, fn ->
+      result =
         list_enabled_rules()
         |> Enum.map(fn rule ->
           case apply_rule(rule, tracks) do
@@ -369,6 +376,9 @@ defmodule MusicLibrary.ScrobbleRules do
             {:error, reason} -> {:error, {rule.type, rule.match_value, reason}}
           end
         end)
+
+      {result, %{scrobble_track_count: Enum.count(tracks)}}
+    end)
   end
 
   @doc """

lib/music_library_web/telemetry.ex

@@ -88,6 +88,13 @@ defmodule MusicLibraryWeb.Telemetry do
         reporter_options: [nav: "Assets"]
       ),
 
+      # Scrobble Rules
+      summary("music_library.scrobble_rules.apply_all_rules.stop.duration",
+        unit: {:native, :millisecond},
+        tags: [:scrobble_track_count],
+        reporter_options: [nav: "Scrobble Rules"]
+      ),
+
       # VM Metrics
       summary("vm.memory.total", unit: {:byte, :megabyte}),
       summary("vm.total_run_queue_lengths.total"),