proxy: fix incorrect connection #send definition never calling super

this made several plugins unusable with the proxy plugin, because a lot
of them are dependent on Connection#send being called and overwritten.
This was done so to avoid piping requests when intermediate
connect-level parsers are in place. So in the way, when the conn is
initial, original send is closed; when not, which should almost never
happen, a second list is created, which is then piped when the
connection is established, back to original send.

lib/httpx/plugins/proxy.rb

@@ -267,10 +267,11 @@ module HTTPX
         end
 
         def send(request)
-          return super unless @options.proxy
-          return super unless connecting?
+          return super unless (
+            @options.proxy && @state != :idle && connecting?
+          )
 
-          @pending << request
+          (@proxy_pending ||= []) << request
         end
 
         def connecting?
@@ -308,6 +309,12 @@ module HTTPX
           when :idle
             transition(:connecting)
           when :connected
+            if @proxy_pending
+              while (req = @proxy_pendind.shift)
+                send(req)
+              end
+            end
+
             transition(:open)
           end
         end

regression_tests/bug_0_24_1_test.rb

@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "support/http_helpers"
+require "support/proxy_helper"
+require "support/minitest_extensions"
+
+class Bug_0_24_1_Test < Minitest::Test
+  include HTTPHelpers
+  include ProxyHelper
+
+  Plugin = Module.new do
+    @requests = []
+
+    class << self
+      attr_accessor :requests
+    end
+
+    self::ConnectionMethods = Module.new do
+      def send(req)
+        Plugin.requests << req
+        super
+      end
+    end
+  end
+
+  def test_proxy_plugin_silencing_conn_send_based_plugin
+    http = HTTPX.plugin(Plugin).plugin(:proxy).plugin(ProxyResponseDetector).with_proxy(uri: http_proxy)
+    uri = build_uri("/get")
+    response = http.get(uri)
+    verify_status(response, 200)
+    assert response.proxied?
+
+    assert Plugin.requests.size == 1
+  end
+
+  private
+
+  def scheme
+    "http://"
+  end
+end