Replace Timeout.timeout with Socket.tcp(..., open_timeout:)

This patch replaces the implementation of #open_timeout from
Timeout.timeout from the builtin timeout in Socket.tcp, which was
introduced in Ruby 3.5 (https://bugs.ruby-lang.org/issues/21347).

The builtin timeout in Socket.tcp is better in several ways. First, it
does not rely on a separate Ruby Thread for monitoring Timeout (which is
what the timeout library internally does). Also, it is compatible with
Ractors, since it does not rely on Mutexes (which is also what the
timeout library does).

This change allows the following code to work.

    require 'net/http'
    Ractor.new {
      uri = URI('http://example.com/')
      http = Net::HTTP.new(uri.host, uri.port)
      http.open_timeout = 1
      http.get(uri.path)
    }.value

Author: osyoyu

lib/net/http.rb

@@ -1654,14 +1654,21 @@ def connect
       end
 
       debug "opening connection to #{conn_addr}:#{conn_port}..."
-      s = Timeout.timeout(@open_timeout, Net::OpenTimeout) {
-        begin
-          TCPSocket.open(conn_addr, conn_port, @local_host, @local_port)
-        rescue => e
-          raise e, "Failed to open TCP connection to " +
-            "#{conn_addr}:#{conn_port} (#{e.message})"
+      begin
+        # Socket.tcp(..., open_timeout:) is a Ruby 3.5+ feature
+        s = if Socket.method(:tcp).parameters.any? {|param| param[0] == :key && param[1] == :open_timeout }
+          Socket.tcp(conn_addr, conn_port, @local_host, @local_port, open_timeout: @open_timeout)
+        else
+          Timeout.timeout(@open_timeout, Net::OpenTimeout) {
+            TCPSocket.open(conn_addr, conn_port, @local_host, @local_port)
+          }
         end
-      }
+      rescue Errno::ETIMEDOUT # We cannot change the exception raised from Socket.tcp
+        raise Net::OpenTimeout
+      rescue => e
+        raise e, "Failed to open TCP connection to " +
+          "#{conn_addr}:#{conn_port} (#{e.message})"
+      end
       s.setsockopt(Socket::IPPROTO_TCP, Socket::TCP_NODELAY, 1)
       debug "opened"
       if use_ssl?

test/net/http/test_http.rb

@@ -246,7 +246,7 @@ def test_failure_message_includes_failed_domain_and_port
     # hostname to be included in the error message
     host = Struct.new(:to_s).new("<example>")
     port = 2119
-    # hack to let TCPSocket.open fail
+    # hack to let Socket.tcp fail
     def host.to_str; raise SocketError, "open failure"; end
     uri = Struct.new(:scheme, :hostname, :port).new("http", host, port)
     assert_raise_with_message(SocketError, /#{host}:#{port}/) do