def call(hash)
      logger.debug { "continuation req_id #{req_id}, got hash: #{hash.inspect}" }
      @rval = hash.values_at(*METH_TO_ASYNC_RESULT_KEYS.fetch(meth))
      logger.debug { "delivering result #{@rval.inspect}" }
      deliver!
    end
def call(hash)
      logger.debug { "continuation req_id #{req_id}, got hash: #{hash.inspect}" }
      @rval = hash.values_at(*METH_TO_ASYNC_RESULT_KEYS.fetch(meth))
      logger.debug { "delivering result #{@rval.inspect}" }
      deliver!
    end
receive the response from the server, set @rval, notify caller