[Enhancement] Capture the number of rows instantiated

lib/mini_profiler/profiling_methods.rb

@@ -17,6 +17,10 @@ def record_sql(query, elapsed_ms, params = nil)
         )
       end
 
+      def report_reader_duration(elapsed_ms, row_count = nil, class_name = nil)
+        current&.current_timer&.report_reader_duration(elapsed_ms, row_count, class_name)
+      end
+
       def start_step(name)
         return unless current
         parent_timer          = current.current_timer

lib/mini_profiler/timer_struct/request.rb

@@ -125,6 +125,12 @@ def move_sql(sql, destination)
           end
         end
 
+        # please call SqlTiming#report_reader_duration instead
+        def report_reader_duration(elapsed_ms, row_count = nil, class_name = nil)
+          last_time = self[:sql_timings]&.last
+          last_time&.report_reader_duration(elapsed_ms, row_count, class_name)
+        end
+
         def add_custom(type, elapsed_ms, page)
           TimerStruct::Custom.new(type, elapsed_ms, page, self).tap do |timer|
             timer[:parent_timing_id] = self[:id]

lib/mini_profiler/timer_struct/sql.rb

@@ -51,12 +51,14 @@ def initialize(query, duration_ms, page, parent, params = nil, skip_backtrace =
           )
         end
 
-        def report_reader_duration(elapsed_ms)
+        def report_reader_duration(elapsed_ms, row_count = nil, class_name = nil)
           return if @reported
           @reported = true
           self[:duration_milliseconds]                += elapsed_ms
           @parent[:sql_timings_duration_milliseconds] += elapsed_ms
           @page[:duration_milliseconds_in_sql]        += elapsed_ms
+          self[:row_count] = self[:row_count].to_i + row_count if row_count
+          self[:class_name] = class_name if class_name
         end
 
         def trim_binds(binds)

lib/mini_profiler_rails/railtie.rb

@@ -114,6 +114,16 @@ def self.initialize!(app)
             Rack::MiniProfiler.binds_to_params(payload[:binds])
           )
         end
+
+        subscribe("instantiation.active_record") do |name, start, finish, id, payload|
+          next if !should_measure?
+
+          Rack::MiniProfiler.report_reader_duration(
+            (finish - start) * 1000,
+            payload[:record_count],
+            payload[:class_name]
+          )
+        end
       end
     end
     @already_initialized = true