introducing the ConnectTimeoutError, releasing it on timeout errors on channels when the channel is still connecting

lib/httpx/channel.rb

@@ -141,6 +141,10 @@ module HTTPX
       end
     end
 
+    def connecting?
+      @state == :idle
+    end
+
     def interests
       return :w if @state == :idle
       readable = !@read_buffer.full?

lib/httpx/connection.rb

@@ -32,8 +32,13 @@ module HTTPX
           monitor.interests = channel.interests
         end
       end
-    rescue TimeoutError,
-           Errno::ECONNRESET,
+    rescue TimeoutError => timeout_error
+      @channels.each do |ch|
+        error = timeout_error
+        error = error.to_connection_error if ch.connecting?
+        ch.emit(:error, error)
+      end
+    rescue Errno::ECONNRESET,
            Errno::ECONNABORTED,
            Errno::EPIPE => ex
       @channels.each do |ch|

lib/httpx/errors.rb

@@ -5,7 +5,15 @@ module HTTPX
 
   UnsupportedSchemeError = Class.new(Error)
 
-  TimeoutError = Class.new(Error)
+  TimeoutError = Class.new(Error) do
+    def to_connection_error
+      ex = ConnectTimeoutError.new(message)
+      ex.set_backtrace(backtrace)
+      ex
+    end
+  end
+
+  ConnectTimeoutError = Class.new(TimeoutError)
 
   ResolveError = Class.new(Error)
 

lib/httpx/plugins/proxy.rb

@@ -119,6 +119,10 @@ module HTTPX
       @pending << [request, args]
     end
 
+    def connecting?
+      super || @state == :connecting || @state == :connected
+    end
+
     def to_io
       case @state
       when :idle