Writes a list of flow processing requests to the database.

def WriteFlowProcessingRequests(self, requests):
    """Writes a list of flow processing requests to the database."""
    # If we don't have a handler thread running, we might be able to process the
    # requests inline. If we are not, we start the handler thread for real and
    # queue the requests normally.
    if not self.flow_handler_thread and self.flow_handler_target:
      if self._InlineProcessingOK(requests):
        for r in requests:
          self.flow_handler_target(r)
        return
      else:
        self._RegisterFlowProcessingHandler(self.flow_handler_target)
        self.flow_handler_target = None

    now = rdfvalue.RDFDatetime.Now()
    for r in requests:
      cloned_request = r.Copy()
      cloned_request.timestamp = now
      key = (r.client_id, r.flow_id)
      self.flow_processing_requests[key] = cloned_request