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

    ֥åȤȤ˸ƤӽФ줿Ȥϡܥǥɤߤ
    HTTPResponse ֥Ȥ֥åϤޤ

    Υ᥽åɤ HTTP ץȥ˴Ϣ㳰ȯޤ

        # example
        response = http.post2( '/cgi-bin/nice.rb', 'datadatadata...' )
        p response.status
        puts response.body          # body is already read

        # using block
        http.post2( '/cgi-bin/nice.rb', 'datadatadata...' ) {|response|
          p response.status
          p response['content-type']
          response.read_body do |str|   # read body now
            print str
          end
        }

