added more level 3 logging using a custom telemetry plugin, which is internal use only

this will therefore not be documented.

.rubocop.yml

@@ -78,6 +78,10 @@ Style/TrailingUnderscoreVariable:
 Style/AccessModifierDeclarations:
   Enabled: false
 
+Style/GlobalVars:
+  Exclude:
+    - lib/httpx/plugins/internal_telemetry.rb
+
 Performance/TimesMap:
   Enabled: false
 

lib/httpx/connection.rb

@@ -268,6 +268,7 @@ module HTTPX
           # dread
           loop do
             siz = @io.read(@window_size, @read_buffer)
+            log(level: 3, color: :cyan) { "IO READ: #{siz} bytes..." }
             unless siz
               ex = EOFError.new("descriptor closed")
               ex.set_backtrace(caller)
@@ -296,6 +297,7 @@ module HTTPX
             end
 
             siz = @io.write(@write_buffer)
+            log(level: 3, color: :cyan) { "IO WRITE: #{siz} bytes..." }
             unless siz
               ex = EOFError.new("descriptor closed")
               ex.set_backtrace(caller)

lib/httpx/plugins/internal_telemetry.rb

@@ -0,0 +1,93 @@
+# frozen_string_literal: true
+
+module HTTPX
+  module Plugins
+    #
+    # The InternalTelemetry plugin is for internal use only. It is therefore undocumented, and
+    # its use is disencouraged, as API compatiblity will **not be guaranteed**.
+    #
+    # The gist of it is: when debug_level of logger is enabled to 3 or greater, considered internal-only
+    # supported log levels, it'll be loaded by default.
+    #
+    # Against a specific point of time, which will be by default the session initialization, but can be set
+    # by the end user in $http_init_time, different diff metrics can be shown. The "point of time" is calculated
+    # using the monotonic clock.
+    module InternalTelemetry
+      module TrackTimeMethods
+        private
+
+        def elapsed_time
+          yield
+        ensure
+          meter_elapsed_time("#{self.class.superclass}##{caller_locations(1, 1)[0].label}")
+        end
+
+        def meter_elapsed_time(label)
+          $http_init_time ||= Process.clock_gettime(Process::CLOCK_MONOTONIC, :millisecond)
+          prev_time = $http_init_time
+          after_time = Process.clock_gettime(Process::CLOCK_MONOTONIC, :millisecond)
+          # $http_init_time = after_time
+          elapsed = after_time - prev_time
+          warn(+"\e[31m" << "[ELAPSED TIME]: #{label}: #{elapsed} (ms)" << "\e[0m")
+        end
+      end
+
+      module InstanceMethods
+        def self.included(klass)
+          klass.prepend TrackTimeMethods
+          super
+        end
+
+        def initialize(*)
+          meter_elapsed_time("Session: initializing...")
+          super
+          meter_elapsed_time("Session: initialized!!!")
+        end
+
+        private
+
+        def build_requests(*)
+          elapsed_time { super }
+        end
+
+        def fetch_response(*)
+          response = super
+          meter_elapsed_time("Session -> response") if response
+          response
+        end
+
+        def close(*)
+          super
+          meter_elapsed_time("Session -> close")
+        end
+      end
+
+      module RequestMethods
+        def self.included(klass)
+          klass.prepend TrackTimeMethods
+          super
+        end
+
+        def transition(nextstate)
+          state = @state
+          super
+          meter_elapsed_time("Request[#{@verb} #{@uri}: #{state}] -> #{nextstate}") if nextstate == @state
+        end
+      end
+
+      module ConnectionMethods
+        def self.included(klass)
+          klass.prepend TrackTimeMethods
+          super
+        end
+
+        def transition(nextstate)
+          state = @state
+          super
+          meter_elapsed_time("Connection[#{@origin}]: #{state} -> #{nextstate}") if nextstate == @state
+        end
+      end
+    end
+    register_plugin :internal_telemetry, InternalTelemetry
+  end
+end

lib/httpx/session.rb

@@ -277,5 +277,9 @@ module HTTPX
     ::HTTPX.send(:const_set, :Session, proxy_session.class)
   end
 
+  if Session.default_options.debug_level > 2
+    proxy_session = plugin(:internal_telemetry)
+    ::HTTPX.send(:remove_const, :Session)
+    ::HTTPX.send(:const_set, :Session, proxy_session.class)
   end
 end