: request_get( path, header = nil )
: request_get( path, header = nil ) {|response| .... }
    path ˤ륨ƥƥޤHTTPResponse
    ֥Ȥ֤ޤ

    ֥åȤȤ˸ƤӽФ줿Ȥϡ֥å¹³
    ݻޤ HTTPResponse ֥Ȥ֥åϤޤ

    Υ᥽åɤ HTTP ץȥ˴Ϣ㳰ȯޤ

        # example
        response = http.request_get( '/index.html' )
        p response['content-type']
        puts response.body          # body is already read

        # using block
        http.request_get( '/index.html' ) {|response|
            p response['content-type']
            response.read_body do |str|   # read body now
              print str
            end
        }

