Net::HTTPGenericRequest#write_header

# File tmp/rubies/ruby-3.3.0/lib/net/http/generic_request.rb, line 399
def write_header(sock, ver, path)
  reqline = "#{@method} #{path} HTTP/#{ver}"
  if /[\r\n]/ =~ reqline
    raise ArgumentError, "A Request-Line must not contain CR or LF"
  end
  buf = +''
  buf << reqline << "\r\n"
  each_capitalized do |k,v|
    buf << "#{k}: #{v}\r\n"
  end
  buf << "\r\n"
  sock.write buf
end