class HTTP::Request::Writer

def send_request
  headers = join_headers
  case @body
  when NilClass
    write(headers)
  when String
    write(headers << @body)
  when Enumerable
    write(headers)
    @body.each do |chunk|
      write(chunk.bytesize.to_s(16) << CRLF)
      write(chunk << CRLF)
    end
    write(CHUNKED_END)
  else fail TypeError, "invalid body type: #{@body.class}"
  end
end