class Excon::Connection

def request_call(datum)
  begin
    if datum.has_key?(:response)
      # we already have data from a middleware, so bail
      return datum
    else
      socket.data = datum
      # start with "METHOD /path"
      request = datum[:method].to_s.upcase << ' '
      if @data[:proxy]
        request << datum[:scheme] << '://' << @data[:host] << ':' << @data[:port].to_s
      end
      request << datum[:path]
      # add query to path, if there is one
      case datum[:query]
      when String
        request << '?' << datum[:query]
      when Hash
        request << '?'
        datum[:query].each do |key, values|
          if values.nil?
            request << key.to_s << '&'
          else
            [values].flatten.each do |value|
              request << key.to_s << '=' << CGI.escape(value.to_s) << '&'
            end
          end
        end
        request.chop! # remove trailing '&'
      end
      # finish first line with "HTTP/1.1\r\n"
      request << HTTP_1_1
      if datum.has_key?(:request_block)
        datum[:headers]['Transfer-Encoding'] = 'chunked'
      elsif ! (datum[:method].to_s.casecmp('GET') == 0 && datum[:body].nil?)
        # The HTTP spec isn't clear on it, but specifically, GET requests don't usually send bodies;
        # if they don't, sending Content-Length:0 can cause issues.
        datum[:headers]['Content-Length'] = detect_content_length(datum[:body])
      end
      # add headers to request
      datum[:headers].each do |key, values|
        [values].flatten.each do |value|
          request << key.to_s << ': ' << value.to_s << CR_NL
        end
      end
      # add additional "\r\n" to indicate end of headers
      request << CR_NL
      # write out the request, sans body
      socket.write(request)
      # write out the body
      if datum.has_key?(:request_block)
        while true
          chunk = datum[:request_block].call
          if FORCE_ENC
            chunk.force_encoding('BINARY')
          end
          if chunk.length > 0
            socket.write(chunk.length.to_s(16) << CR_NL << chunk << CR_NL)
          else
            socket.write('0' << CR_NL << CR_NL)
            break
          end
        end
      elsif !datum[:body].nil?
        if datum[:body].is_a?(String)
          unless datum[:body].empty?
            socket.write(datum[:body])
          end
        else
          if datum[:body].respond_to?(:binmode)
            datum[:body].binmode
          end
          if datum[:body].respond_to?(:pos=)
            datum[:body].pos = 0
          end
          while chunk = datum[:body].read(datum[:chunk_size])
            socket.write(chunk)
          end
        end
      end
    end
  rescue => error
    case error
    when Excon::Errors::StubNotFound, Excon::Errors::Timeout
      raise(error)
    else
      raise(Excon::Errors::SocketError.new(error))
    end
  end
  datum
end