Writes a list of message handler requests to the database.

def WriteMessageHandlerRequests(self, requests):
    """Writes a list of message handler requests to the database."""
    now = rdfvalue.RDFDatetime.Now()
    for r in requests:
      flow_dict = self.message_handler_requests.setdefault(r.handler_name, {})
      cloned_request = r.Copy()
      cloned_request.timestamp = now
      flow_dict[cloned_request.request_id] = cloned_request